2021 GMC SIERRA 1500 Engine Problems

The contact owns a 2021 GMC Sierra 1500. The contact stated that after driving on a trip, the contact noticed that the vehicle had lost 10 MPG after a software update was performed. The check engine warning light was illuminated. The vehicle was taken to Richardson Chevrolet (3825 S Huron Rd, Standish, MI 48658), who confirmed that the vehicle was working as designed. The check engine warning light was reset. The vehicle was not diagnosed or repaired. The manufacturer was contacted and opened a case, and referred the contact to the NHTSA Hotline for assistance. The failure mileage was approximately 57,000.

Mileage: 57,000

2021 gmc purchased brand new Truck had complete engine failure lifters and rods were replaced at 7000 miles under factory warranty lost complete engine power GMC says we are not on any recall and they refused to buy back the truck or give me an extended warranty they said this year 2021 with 5.3 doesn’t have engine issues.

I own a 2021 GMC Sierra 1500 equipped with the 6.2L L87 V8 engine and 10-speed transmission. The vehicle exhibits the following issues: Persistent lifter ticking noise audible from the driver-side wheel well, even when the engine is warm. Rough idle that is noticeable at stops and low-speed conditions. Transmission shifting problems, specifically harsh or delayed shifts when downshifting from 3rd to 2nd gear during deceleration. These symptoms raise concerns about potential lifter failure and transmission defects. I am aware of GM’s recall (25V-274) and NHTSA Engineering Analysis EA25007, but my vehicle’s build date (January 2021) currently falls outside the official recall window. Given the similarity of symptoms to those under investigation, I believe my vehicle may be affected by the same defect. Safety Concern: The rough idle and shifting hesitation could lead to unexpected loss of power or unsafe driving conditions, especially during deceleration or merging. Request: Please include this complaint in EA25007 and consider expanding the recall to cover earlier builds. I am willing to provide service records, videos, and additional documentation upon request.

Motor was chugging took to a dealership on march 22 was told I had a collapsed lifter I was told my cost would be 4800 gm would cover half which was fine then when the work was done the dealership took it for a test drive while they were on the test drive the motor locked up they originally told me it was a cam bearing later I found out through paperwork that was emailed to me that it was a main bearing which is consistent with the recall but my vin number hasn’t came up it’s a 2021 gmc sierra 1500 with a l87 6.2 and it cost me 6200 I was 10,000 miles out of warranty

Faulty lifters replaced on passenger side. Had only 25000 miles on engine. GM extended warranty on thousands with this engine but not mine. Have only 28000 miles on truck and just turned 5th year so warranty is void. GM should extend warranty on all vehicles with this engine.

TRAVELING ON INTERSTATE GOING AT THE POSTED SPEED LIMIT AND TURNED OFF THE INTERSTATE ONTO MY EXIT TURN AND VEHICLE ENGINE STARTED KNOCKING AND ENGINE SHUT OFF OIL WARNING LIGHT CAME ON ALL WHILE TRYING TO STOP THE VEHICLE AT THE CROSS TRAFFICE STOP SIGHN AND ENDED UP STOPPED IN THE MIDDLE OF ANOTHER HIGHWAY BARLEY MISSING THE CROSS TRAFFIC COMING AT ME FROM BOTH DIRECTIONS. THIS HAPPENED AT I94 AND COUNTY HIGHWAY 34 AT BARNESVILLE MINNESOTA EXIT. THIS SUDDEN ENGINE FAILURE NEARLY KILLED ME AND THE 2 VEHICLE DRIVERS THAT NEARLY STRUCK MY TRUCK FROM BOTH DIRECTIONS. GMC WOULD NOT HELP ME WITH MY REPAIR OF OVER $11000.00 DOLLARS FOR A NEW CRATE MOTOR FROM GMC. SITING MY TRUCK DID NOT FALL UNDER THE L87 RECALL. FAILURE ROD BEARINGS AND CRANK BEARINGS WITH A TON METAL SHAVINGS IN THE OIL AND FILTER. NO WARNING THIS WAS GOING TO HAPPEN. MY TRUCK HAD 95000 MILES ON IT WHEN IT NEARLY KILLED ME AND OTHERS. INDEPENDENT SERVICE CENTER JOHNSONS AUTO REPAIR IN MOORHEAD MN INSTALLED THE NEW CRATE MOTOR FROM LUTHER GMC FARGO ND.

Complete engine power loss.

The coolant control valve has failed on two occasions—once during the warranty period and again approximately 18 months later, outside of warranty. Each failure resulted in continuous fan operation and fluctuating engine temperatures. Failed on around June 2024 and again December 17, 2025

mechanical and electrical issues with my GMC Sierra Elevation Duramax Diesel, purchased in 2021. Despite multiple dealership visits, diagnostic evaluations, repairs, and software updates, these issues persist and have significantly impacted the reliability and safety of the vehicle. In December 2025, my vehicle was taken to the dealership for diagnostics and a third software update intended to resolve recurring engine-related faults. Throughout 2025, the check engine light illuminated on approximately 30 occasions, confirmed by at-home diagnostic scans. The same diagnostic code related to the 1) SCR NOx Catalyst Efficiency Below Threshold Bank 1 Catalyst 2 P2C7A - Engine I 2) Exhaust Gas Recirculation (EGR) Cooler Efficiency Below Threshold P14D9 - Engine has appeared repeatedly since the vehicle was first purchased in 2021. Additionally, on approximately 15 occasions in 2025, the vehicle failed to start. When pressing the ignition button, the engine screeched while attempting to turn over for 20 to 45 seconds, after which the vehicle powered off entirely. After waiting approximately 10 minutes, the vehicle would then start normally. Notably, during these no-start events, no check engine light or diagnostic code appeared, and the engine light and starting failure have never occurred simultaneously. hese same concerns were explicitly explained to service technicians during the most recent recall repair in 2025. I was informed that a software update would resolve the issue. However, the problems have continued. A similar frequency of failures occurred throughout 2024. At that time, GMC advised that the issue was likely the vehicle’s battery. Acting on this recommendation, I had the battery replaced at my expense in October 2024 by the dealership. This repair did not resolve the issue. From the time of purchase in 2021 through January 2024, these same symptoms occurred approximately 10 times, demonstrating a long-standing and unresolved defect.

Had a "Trans Hot Warning" light. Dealership said it was internal valve body failure. They said there is recall on this for other engine types even though this is same issue. I think GMC needs to expand their recall.

The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the engine seized. The contact was unaware of a warning light being illuminated. The contact stated that while attempting to start the vehicle, the vehicle failed to start. The vehicle was towed to the dealer, where it was diagnosed with engine failure. The contact was informed that the engine needed to be replaced. The vehicle was not repaired. The contact referenced an unknown engine recall; however, the VIN was not under recall. The manufacturer was made aware of the failure, and a case was filed. The contact was advised to report the failure to the NHTSA Hotline. In addition, the contact was informed that the VIN for the vehicle was a Canadian VIN, and the mileage was displayed in kilometers. The failure mileage was approximately 120,000.

Mileage: 120,000

Heard a ticking noise then check engine light started blinking along with service esc and parking brake. Took it to the dealer and I had a bad lifter again. I was previously repair for lifters under warranty a little over 2 years ago.

On 10/21/2025 as I was traveling on the highway in Kansas at 60 mph, the vehicle lost power and the engine went into limp mode immediately reducing the speed dramatically. Multiple warning lights flashed on the screen. I was able to get the truck to the side of the highway. The vehicle never started again. I was informed by the dealer that the vehicle would need a new engine.

The engine is knocking and running rough. I took it to Christian Brothers Automotive in Newnan Ga and the advised engine replacement.

I purchased a 2021 GMC Sierra 1500 Denali (VIN: [XXX] ) from J.C. Lewis Ford in Pooler, Georgia. The dealership did not disclose an active federal safety recall (NHTSA Campaign Number: 24V-xxx / GM XXX) related to engine connecting rod and crankshaft defects that can result in sudden engine failure and loss of propulsion. The Blue Certified delivery document they had me sign includes a section requiring disclosure of any open recalls, but they left the recall section blank and checked that all recalls were explained to me. No disclosure of any recall occurred during the sale. The vehicle developed engine problems within days and is currently in GMC service. The nondisclosure put me at risk of driving a vehicle with a known safety defect. I am reporting this as a dealer nondisclosure of a federal safety recall. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

The contact's grandson owns a 2021 GMC Sierra 1500. The contact stated that after the vehicle was purchased from a private seller and driven 258 miles, while his grandson was merging off the exit ramp, the engine seized. The low oil pressure warning light was illuminated. The contact stated that the check engine warning light was illuminated prior to the failure. The vehicle was towed to the contact's residence. The contact scanned the vehicle and retrieved DTCs: P0011, P0016, P006DD, and P0521, stored DTCs: P06DD P0011, and permanent DTCs: P0011 and P0016. The engine was replaced by the contact. The local dealer was contacted for parts. No further information was available. The manufacturer was not contacted. The failure mileage was approximately 100,148.

Mileage: 101,148

I just surpassed my extended warranty (5 year/100,000 miles) by a couple of thousand miles and my coolant control valve has gone out. The problem is so common that the part is on back order for months at a time. GM says that they issued special coverage for 2020-2022 models, but my dealer is telling me that my VIN is not covered. They want to charge me $2,400 to replace it. This is insane. It’s a very common problem that they know about and it’s going to almost break me. We need help!

ENGINE BURNING OIL AND BLOWING WHITE SMOKE OUT TAIL PIPES. HAVE TO ADD OIL EVERY 1500 MILES OR SOONER IF TOWING. HAS BEEN AN ISSUE SINCE FIRST OIL CHANGE. VEHICLE IS NOW AT 88057 MILES

While traveling to work at 75mph, a sudden an unexpected malfunction of internal engine components caused a loss of propulsion.

I was traveling home from work and lost all power to the vehicle while driving. No warning lights, check engine lights came on. I was able to cross traffic and park it in a business place. I had it towed to a chevy dealership for diagnostic. They said that the timing chain came off and i would need a new engine. I had it towed to a auto mechanic shop for a second opinion and they gave the same result. The vehicle is only 4 years old with 92,000 miles on it. When i lost all power to the vehicle, I did not hear any strange noises.

I am an active U.S. Air Force member. My 2021 GMC Sierra 1500 failed GM Recall N252494003 on Sept 29, 2025 (L87 engine loss of propulsion). GM states this defect can cause sudden engine failure and loss of propulsion, increasing crash risk. Despite the confirmed failure, Ocean Cadillac (Miami, FL) told me to keep driving the unsafe vehicle and refused all Courtesy Transportation. The Service Manager admitted in writing that the engine failed, the defect can cause loss of propulsion, and the replacement engine is delayed under GM National Control for up to 3 months — yet they still denied me a loaner or rental. His statements contradict the GM documents he attached: • GM Bulletin DCS7222 says Courtesy Transportation CAN be provided during L87 recall downtime and dealers MUST consider loaners/rentals. • GM FAQ N252494002 says Courtesy Transportation IS available for this recall. • GM FAQ lists recall symptoms (check engine light, hesitation, high RPM, reduced power) — NOT battery drain. • GM states: “If the engine fails, the vehicle WILL lose propulsion.” Ocean Cadillac ignored these rules and put me back on the road in a known unsafe vehicle. As an American manufacturer, GM has a responsibility to protect American drivers. Their failure to follow recall procedures placed me, my family, and other motorists at risk. I request NHTSA investigate whether GM/Ocean Cadillac are complying with recall safety requirements and whether customers are being told to drive unsafe vehicles after confirmed failures.

Took the vehicle to the dealer because of an engine noise. It had issues with the valves knocking when it had around 1000 miles. I took it in and now the truck has around 67,000 miles and I’m being told it needs a new engine because of a bent rod in the engine. I was told that I need a new engine. Previously I had a lot of other issues with the front wheel hubs clicking. But, this truck didn’t even make it to 5 years and now it needs an engine.

I own this 21 GMC Sierra with a 6.2L. This vin is not part of your current recall. But my truck is at a dealership waiting on a replacement engine. I was told that the engine locked up in the bay. Not sure if any lights came on before the engine failed, the dealer did not go into that much of detail. The truck is sitting outside waiting on the engine, not sure if gm made then do any failure analysis or just said its a 6.2 were sending an engine.

My wife was driving at highway speeds with all are kids when the trucks motor suddenly loss all power all check engine lights illuminated and what I'm assuming had major engine failure causing rod knock.

On [XXX], at approximately 15,873 miles and while on the freeway approximately 30 miles from my home, my GMC Sierra 1500 with the L84 engine experienced a failure of the DFM lifter assembly. This required a significant engine disassembly and the replacement of multiple valvetrain components. This repair was performed at Gold Rush Chevrolet in Auburn, CA, as documented in the enclosed service invoice. GM has issued Technical Service Bulletins and product communications addressing similar lifter failures in Gen V small-block V8 engines with DFM/AFM, including Service Update N212353840, PIP5776, #19-NA-219, and related updates. Industry coverage and owner reports and current Class Action Lawsuits indicate that these failures can recur, even after initial repairs, due to the high cycling frequency of the DFM lifters. Given the nature of the defect and GM’s documented acknowledgement of the issue, I am requesting that GM extend the powertrain warranty coverage for the engine and related valvetrain components for a period of 10 years,100,000 miles as a goodwill policy adjustment. A warranty extension would ensure customer confidence and protect against the significant cost of a repeat failure. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

After having transmission issues which was replaced under warranty, within 300 miles, the engine failed. The vehicle has now been sitting at the dealership since October 7, 2025 waiting for a replacement engine. There is no timeline available for the replacement engine as they are currently backordered. Absolutely ridiculous.

I just took my 2021 GMC Sierra 1503.0 Duramax diesel into Faulkner Nissan, today 10/18/2025 m, to have that recall fixed. I picked it up from the dealership and drove about 10 miles before it went into limp mode and reduced power mode while I was driving and started to shift very roughly and I’ve never had any issue like this before they supposedly fix this recall, I think the software patch made it worse in my case. Now my vehicle is throwing a bunch of different transmission error codes, that it has never produced , and it is going into reduced power mode,as I’m driving and going into limp mode as I’m driving, which you never has done before And it feels like it’s stuttering in early gears now and the idle was really rough it didn’t idle at a specific spot it went from 800 to 1300 back down to 800 when it should’ve just been idle at 800. I don’t know what to do. It seems like this recall made the problem worse for me and my truck in this case, I don’t know what to do and I don’t know where to go. I hope you guys can help us. Please make GMC take responsibility Before somebody gets killed. If they haven’t already this issue is extremely DANGEROUS AND I’M SURE IS DESTROYING THE TRANSMISSION. I don’t feel comfortable driving my family in my vehicle anymore because of this issue it is terrifying….

I was driving at highway speeds probably doing 55 and another vehicle pulled out in front of me forcing me to slow down rapidly. That’s when my wheels locked up and my vehicles wheels locked up in the middle of the highway. Screeching tires, almost like the vehicle went into park for a second. After about two seconds, I was able to continue driving a highway speed no check engine lights no error codes. It felt like I just hit something nearly gave me a heart attack. My family was in the car. It felt like we all almost died. It was terrifying. This transmission issue recall situation has happened to me more times than I can count. Now it’s almost a guarantee that if you have to shift too hard too fast it locks up the differential and it is terrifying. Every time.

This was the first time I had ever experienced the rear differential locking up at highway speeds in my truck. It was probably the day after I bought the truck. I was going down route one southbound going probably around 60 miles an hour and the wheels locked up and the vehicle felt like it was gonna come to a screeching hole. It felt like I hit something And then the wheels unlocked and it allowed me to keep driving. I thought that I might have hit the cruise control button on the steering wheel by accident and chopped it up to operator error which now I know is one of the most dangerous recall issues I’ve ever had to experience or indoor. Thank goodness my family was not with me at the time. But these issues continued on for months…

DTC CODE P1098 PRESENT RELATED TO FAULTY COOLANT CONTROL VALVE ON 3.0 DURAMAX DIESEL ENGIINE. THIS IS A KNOWN ISSUE WITH THIS ENGINE AND IS SUPPOSED TO BE COVERED UNDER THE 100K MILE POWERTRAIN WARRANTY. PREVIOUSLY TOOK VEHICLE INTO DEALERSHIP FOR REPAIR INVOLVING REPLACEMENT OF THE COOLANT CONTROL VALVE BUT WAS TOLD REPROGRAMMING OF THE ECM WAS REQUIRED FIRST STEP PER GM REPAIR BULLETIN. REPROGRAMMING COST ME $195 AND WAS TOLD THIS WAS NOT COVERED UNDER THE 100K POWERTRAIN WARRANTY. NOW, A FEW MONTHS LATER, THE SAME ISSUE AND DTC CODE P1098 HAPPENED AGAIN WHILE DRIVING ON FREEWAY AT FREEWAY SPEEDS AND CAUSED VEHICLE COMPUTER TO LIMIT SPEED OF THE VEHICLE WHICH CAUSED HAZARDOUS SITUATION IN CONSTRUCTION ZONE AS WAS NOT ABLE TO MAINTAIN SPEED OF TRAFFIC WHILE TOWING TRAILER WITH BOAT. I ALSO UNDERSTAND THAT GM HAS ISSUED SPECIAL EXTENDED WARRANTY RELATED TO THIS COOLANT CONTROL VALVE IN SEPTEMBER 2025 WHICH EXTENDS THE WARRANTY COVERAGE UP TO 15 YEARS AND/OR UP TO 150K MILES BUT I WAS TOLD AT THE DEALERSHIP THAT MY VIN# DOES NOT QUALIFY FOR THIS EXTENDED COVERAGE FOR SOME UNKNOWN REASON?

Vehicle showing signs of a failing coolant flow control valve and/orcoolant temperature sensor. - AC takes a long time to cool down - Engine fan will stay on after the vehicle is shut off - I often see the notice of “A/C Off Due To High Engine Temp” From what I can find, this issue I’m experiencing is a known point of failure in this vehicle make/model/year. On 10/10/2025, I took the vehicle to Fountain Buick GMC Service in Orlando, FL. The service manager recognized the symptoms immediately, and even knew right away that the part to fix it was on back order - further bolstering that it is an issue that GM is aware of and deals with regularly. Per the service manager, GM’s initial response was to issue a “pay to play” software update that is covered under the 3yr/36,000 warranty, but not the 5yr/100K. Out of warranty, this “solution” costs $499.99, and has a < 10% degree of success. If the update doesn’t fix the issue, then it would be covered. However, the need for the software update was not communicated to consumers. Regardless, since the issue is not yet severe enough to be recognized via code (despite symptoms, pictures, and video), GM will not take any action under warranty towards fixing it at this time. The vehicle’s 5yr/100K warranty expires on 10/15/2025. If the code throws on 10/16/2025, it will not be covered under warranty, but *may* be covered under dealer assistance. And regardless, the $499.99 charge will apply, independent of warranty coverage. More important than the money is the safety. The engine’s temperature is not being regulated, the symptoms I’m experiencing are terminal, and this issue will not be fixed on its own.

Constant engine issues, cams, lifters. Transmission problems. These engines in these vehicles need to be RECALLED. I have bought 6 of these trucks and all of them have the same issues. SPENDING 14k on new engines one after another is ridiculous. These are classified as “work” trucks and can’t handle “working”

Engine lifters bent a pushrod and scratched my camshaft in my engine causing me to be stranded with minor children. 3rd time since I bought this in 2021 that I have had engine faults in this truck.

Complete engine failure on July 17, 2025, related to current recall for defective engine parts on 6.2L V8 L87 engine. Towed to dealer same day. Dealer continues to report no ETA available on replacement engine. Dealer has had possession of my unrepaired truck for 46 days now and counting.

Coolant control valve failure. Instantly reduces power on truck. National back order on parts. No remedy.

Have owned my 2021 GMC Sierra 1500 with the 3.0 Duramax for a year and the check engine light has come on multiple times for a "Coolant Control Valve" issue. The truck runs the fans at 100% and puts the truck into reduced power at least once a day. I have read that GM sometimes will not cover this repair under powertrain warranty even though it's an engine problem. Please fix this issue! To answer the previous questions, the coolant control valve is malfunctioning, and the truck is currently at the dealer being inspected. Yes the dealer has said this issue is common on these trucks (confirmed by National GMC in American Fork, Utah). Yes the check engine light has appeared multiple times. These issues started appearing in June 2025

I receivd a recall on my 2021 GMC Denali 1500 , 6.2 engine Recall # N252494000. made an appointment with Carroll GMC, at 1455S. Tamiami Trail, Venice , Fl, on 7/29/25 at 11AM. I showed up for my appointment and they denied checking my truck on the recall stating they did not have the remedy to fix the problem so therefore they were not going to check my truck for the recall...... I have a trip coming up and now I a afraid to go on the highway in case my truck loses power and I get in an accident............ MY truck should have been checked for the recall regardless of the remedy to fix it..So at least I know weather it is safe to drive or not

This vehicle experienced catastrophic engine failure while I was on vacation 400 miles from home. I have researched this failure and there is a class action lawsuit against GMC. My truck has been at the dealer for 25 days and still waiting for authorization from Fidelity Warranty Services. Considering it’s such a common problem I feel GMC should be paying for this. At the very least the warranty company is aware of this problem and purposely delaying the authorization to repair. I just bought a new camper which I cannot use. I am fisherman and cannot use my boat. My beach pass is also on the vehicle. So essentially my summer has been ruined by a company that produced a faulty vehicle and didn’t discord this information to me.

⸻ Background: •2021 GMC Sierra Denali – 6.2L V8 •VIN included in GM’s engine defect recall (connecting rod/crankshaft) •Recall status shows “No current remedy available” •Defect acknowledged by GM can cause “engine damage, loss of propulsion, or complete engine failure.” Timeline of Events: •~1 month ago – Truck began running rough with noticeable ticking/knocking noise. •Dealer could not schedule appointment for 3 weeks. •08/08/2025 – Dealer inspection confirmed failed lifters and damaged camshaft. •Repair estimate: $9,300 (see attached dealer estimate). Connection to Recall: •Lifter and camshaft are internal engine components dependent on the same lubrication and oiling system as the crankshaft/connecting rods cited in the recall defect. •The defect’s potential to contaminate oil and cause internal engine damage makes this failure consistent with recall-related damage.

This recall has been coming for some time now its out and GM still has no plan or action. This is our only auto and my understanding if this issue happens it could cause loss of life. I am concerned for my wife driving to work every day and what happens if we want to take a trip. We need resolution on this. Apr 24,2025 Manufacturer Recall NumberN252494000 NHTSA Recall Number25V274 Recall StatusRecall Incomplete, remedy not yet available [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Coolant Control Valve is faulty. Part number 24001355 for my GMC Diesel Sierra 1500. The check engine light goes on and sometimes the engine power will be cut in half to protect the engine. It can be inspected when needed. My truck cannot go as fast and the Engine fans sound very loud to cool down the engine. I was 3 hours away from my house when this happened the first time and I wasn’t sure I would make it home. I had to let the engine cool down for about 6 hours after I pulled off of the highway. This has happened two times so far and happens when the AC is on and sometimes when you use the remote start it won’t start the truck remotely and the check engine light goes on. The problem started in July 2025 with 51,000 miles. The engine control module code is P1098. I have asked my GMC dealership to look at the issue and they have told me that the part is backlogged for at least 2 months and they will not look at my truck until the part is available. I haven’t had any other issues with the engine so far and this was the first time a check engine light has gone on.

The contact owns a 2021 GMC Sierra 1500. The contact stated while driving approximately 40 MPH, the check engine warning light started flashing and the vehicle was shaking with a misfire coming from the engine. Additionally, there was black and greyish smoke coming from the tailpipe. The Roadside Assistance request message was displayed on the instrument cluster. The vehicle was taken to a dealer where it was diagnosed with a misfire. The vehicle was not repaired. The vehicle was taken to the residence, but the failure persisted. The vehicle was taken to an independent mechanic to be diagnosed, and it was determined that the lifter had dropped, and the engine needed to be replaced. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was unknown.

I own a 2021 GMC Denali with a 6.2L V8 L87 engine and 45,500 miles. I have confirmed the presence of metal shavings in the oil and oil filter, indicating that the engine is beginning to fail. When I took the vehicle to my local dealership, I was informed that there is currently no fix for this issue and was advised to continue driving the vehicle. This poses a serious safety risk—not just to me and my family but also to others on the road. A sudden loss of power could lead to a dangerous accident, and I do not want to be responsible for something preventable that could harm innocent people. My concern is that GM is aware of this engine issue but has instructed me to keep driving the vehicle, despite the known defect. How can GM be allowed to avoid accountability for such a critical safety matter? If a fatal accident were to occur, would the responsibility fall on GM or the NHTSA for failing to act? It’s also troubling that GM continues to profit by selling new vehicles, including the 2025 models, with similar issues, all while neglecting to provide solutions for affected customers like me. I purchased this $80,000 truck in good faith, but now no dealer wants to trade or buy these trucks without me taking a significant financial loss—something GM should be responsible for. As a taxpayer, I find it unacceptable that we bailed out GM in the mid-2000s, yet they continue to disregard accountability for their actions. I urge the NHTSA to take this issue seriously. A specific deadline should be set for GM to resolve this issue, and they should face daily penalties for every day they fail to provide a fix. If no resolution is possible, full refunds should be mandated. Please address this issue promptly, as it affects real people’s safety and financial well-being every day.

The coolant control valve (Part # 24001355) has failed. Apparently this is the case with many vehicles and GM will not/can not get replacement parts. This should be a recall.

P1098 Code - Coolant Control Valve on/off/on/off.

When I started my truck in the morning I noticed the check engine light came on and my engine fan started running really loudly. I shut my truck off and let it sit for 5 minutes and restarted it in hopes the check engine light would not appear. Unfortunately it did come back on and the engine fan began running really loudly again. I drove the truck to the nearest mechanic and you could feel the truck was trying to counter the problem by forcing me to drive it in a lower speed. After taking it to a shop to get it scanned to see what the code was. The mechanic said it was reading code P1006 three times. He said this coolant system and is why my engine fan was triggered to run really loudly. But the engine was not over heating as all other indicators showed that temps were normal. The mechanic believes it could possibly just be a faulty wire. However after talking to GM he said if it is this coolant part that needs to be replaced, it could take up to months to fix as the part is on national backorder. Doing more research, it appears others have had this same problem and GM even knew shortly after this model was released that this would happen.

The check engine light came on at one point. I took it to figure out why the check engine light was coming on and the scanner indicated that the NOX catalyst was below threshold. I researched it and it is a common issue. The check engine light eventually turned off after a couple of days. About 2 weeks later it came back on. I noticed as i was driving the coolant fans were running at 100% meaning that they were blowing long and hard. So I scanned it and it said that the engine coolant valve was at fault. This is also a common issue with the vehicle, particularly in the 2021 GMC Sierra 1500 3.0 Turbo Diesel. It is a faulty part and it costs thousands of dollars to replace. How can these two issues not be on a national recall by GM? They are too common and very expensive to repair. This issue is so common that now the valve is on a national back order. Meaning the parts may not be available for 30-120 days. The vehicle is not safe to drive with a bad engine coolant valve. I have now a rental car for the past 7 days while my truck sits waiting for a valve to arrive and pay thousands in repair just to drive it again.

wn a 2021 GMC Sierra 1500 6.2L (VIN: [XXX] ), which is now experiencing a severe misfire, engine ticking, and diagnostic code P318A. I’ve confirmed this issue is related to GM Recall N252494001 for engine connecting rod/crankshaft failure. However, I’ve been told my VIN has not yet been activated for recall repairs, and both the local dealership and GMC support have refused to escalate my case or offer assistance. This is a known safety issue, and I’m now at risk of total engine failure and significant financial loss while waiting for GM to act. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

The contact owns a 2021 GMC Sierra 1500. The contact received notification of NHTSA Campaign Number: 25V274000 (Engine and Engine Cooling). The contact stated that while driving at approximately 50 MPH, there was a loud squeaking sound coming from the front driver’s side of the vehicle before the vehicle lost power. Simultaneously, the check engine warning light started blinking. The vehicle was pulled over to the side of the road and the sound became louder, before becoming a knocking sound. The vehicle was restarted, and the failure persisted. The vehicle was towed to the residence. The vehicle was not diagnosed or repaired, but a dealer stated that there was as recall associated with the VIN; however, parts were not yet available to repair the vehicle. The manufacturer was not notified of the failure. The failure mileage was approximately 128,000. VIN tool confirms parts not available.

Mileage: 128,000

My 2021 GMC Sierra 1500 with L87 engine, covered by recall 25V274. None of my local dealers are inspecting for this recall. This truck is my daily driver and I routinely drive on interstates for my work. GM has been slow to address this major manufacturing defect and has not remedied the problem. My truck is no longer worth what is was previously and is lowering trade in or sale value. I am requesting that GM buy back my vehicle due to ongoing safety risks and loss of value.

Was informed from by GM that my vehicle is involved with a recall an still hasn't been repaired

On Dec 27 I noticed a skip in my engine when I started the truck. I took the truck to Cronic Buick GMC on Jan 6 for an inspection. They reported to me that the engine failed.Seized up. I reported the incident to my extended warranty company Warranty Solutions. They refused to do the repair because I was late for an oil change in 2022. After 3 weeks and no cooperation I contacted GM customer service. I was assigned an agent that help initiate the engine repair . The repair was completed on April 12 (3 months after the failure). I paid $4600 out of pocket for a portion of the engine repair .

What component or system failed or malfunctioned, and is it available for inspection upon request? The valvetrain system failed due to broken rocker arms, which resulted in additional internal engine damage. This failure occurred under normal driving conditions. The affected components have not yet been discarded and are available for inspection upon request.How was your safety or the safety of others put at risk? The failure caused sudden engine misfiring and knocking, reducing engine power while I was operating the vehicle. This significantly compromised acceleration and response time, especially during merging and lane changes, which could have led to an accident. Any unexpected loss of power or engine instability at highway speeds poses a serious risk to myself, passengers, and other motorists.Has the problem been reproduced or confirmed by a dealer or independent service center? Yes. The issue has been diagnosed and confirmed by an independent certified mechanic, who verified the broken rocker arms and resulting engine damage during inspection.Has the vehicle or component been inspected by the manufacturer, police, insurance representatives, or others? The vehicle has not yet been inspected by the manufacturer, police, or insurance representatives. Only a certified independent mechanic has inspected the failure thus far.Were there any warning lamps, messages, or other symptoms of the problem prior to the failure, and when did they first appear? Yes. The check engine light appeared and the engine began running rough and producing a knocking sound. These symptoms occurred just prior to the confirmed failure and prompted me to stop driving the vehicle immediately and have it inspected. Given the seriousness of this issue and reports from other GMC 5.3L engine owners experiencing similar rocker arm failures, I urge the NHTSA to investigate this potential defect. It poses a real and significant safety risk.

Replacement part needed is COOLANT CONTROL VALVE according to diagnostics at local GM dealer service department after noting check engine light was on. YES, it is available for inspection. Told unsafe to drive as it would very likely overheat or worse. It has been in the shop for a month (as of June 11, 2025) awaiting a backordered part, which we’re told is a national backorder. No loaner vehicle available and told by service department that they have had another truck in for same problem for several months and that this problem is very common. PLEASE HELP us with getting the part needed!

The coolant control valve on my truck is causing issues. From doing research, this is an ongoing issue with the 3.0 duramax. The part is on nationwide backorder and I cannot drive my vehicle in reduced engine power because the only way I can get to work is by taking the interstate. It is madness that GM has not issued a recall or done anything to rectify this issue. Many GMC owners are paying on vehicles that they are unable to drive which is assanine. This part needs to be readily available due to the NUMEROUS complaints that have already been submitted in regards to this part.

The contact owns a 2021 GMC Sierra 1500. The contact stated that upon starting the vehicle, there was an abnormal knocking sound coming from the engine. The abnormal sound ceased once the vehicle had accelerated; however, the abnormal sound returned while the vehicle was idling. The check engine warning light was illuminated. The vehicle was taken to the dealer where it was diagnosed that the ball bearing caused a misfire, and two cam lifters needed to be replaced. The vehicle was repaired. The contact picked up the vehicle and on the way home, the engine failed. The contact took the vehicle back to the dealer. The technician test drove the vehicle with the contact as a passenger, and the check engine warning light illuminated. In addition, there was an abnormal sound coming from the engine. The vehicle failed to accelerate as intended while depressing the accelerator pedal. The contact was informed that the engine failed and needed to be replaced along with the fuel body system. The contact was informed that as per GMC, the oil needed to be changed to an oil with a thicker viscosity. The fuel body was replaced, and the oil was changed. The manufacturer was made aware of the failure and offered the contact an amended warranty. The contact was informed that GMC had elected to participate in the procedures under the Song Beverly Act. The failure mileage was approximately 50,000.

Mileage: 50,000

The contact owns a 2021 GMC Sierra 1500. The contact stated that upon starting the vehicle, the vehicle was idling abnormally, prompting the contact to turn off the vehicle. The contact stated that the check engine warning light was illuminated. The vehicle was taken to the dealer, who diagnosed a failure with the lifter in cylinder #4. The contact stated that the lifter had collapsed into the engine, causing damages to the engine and camshaft. The vehicle was repaired. The manufacturer was not notified of the failure. The failure mileage was 98,000.

Mileage: 98,000

It started with a emergency brake light coming on, shortly (2 miles) later it started misfiring on cylinder #1 after replacing coil pack plug wire and plug. It then started smoking bad out of the exhaust. I knew GM was having recalls on the 6.2 engines so I hauled it to the dealer. They told me it was a bad engine and since it had aprox.62,000 miles on it and no recall it wasn't covered. Since then the dealer called the factory service rep. and he agreed to replace the engine at a 50% reduction in the price, but had no idea when they could get me a replacement engine. After a few days of research on my part I called the dealer again to get a price on how much it was going to cost me? The owner of the dealership ask me to give him a few more days to ask the rep. if he would agree to 100%. My problem now is I don't have it to drive, I can't sell it. and no idea how long it will be before it can be repaired. Plus I am still making payments on it. It is available for inspection at the dealer. If I had of continued to drive, it could have locked up causing a catastrophic accident. In my research it looks like these problems started in 2019 not late 2020 when mine was built. NC has lemon law complaints going back to 2019 that have been paid out. I currently own a #1 2007 GMC Yukon Denali 6.2 with aprox.389,000 miles and only replaced the transmission recently. #2 A 2008 GMC Sierra Denali 6.2 with 279,052 miles, new transmission. #3 A 2011 GMC Yukon Denali 6.2 with 234,361 miles and #4 a 2017 Cadillac Escalade 6.2 with aprox. 102,000 miles. All of these are working and driving on a daily bases. I have a lot of faith in these 6.2 engines until now, I will no longer be buying any more of these engines even though 1 out of 5 aint bad. Thank you for your consideration and for what you do. [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

The contact owns a 2021 GMC Sierra 1500. The contact stated that occasionally while attempting to start the vehicle, the engine hesitated to turn over. The contact stated that the failure progressed, and the vehicle no longer started as needed. The check engine warning light was illuminated. The contact stated that two local dealers were contacted; however, the contact was advised that to diagnose or repair the vehicle, might take several months. The vehicle was towed to a local independent mechanic, where it was diagnosed with camshaft sensor failure. The vehicle was not repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 83,000.

Mileage: 83,000

Safety recall, unsafe

Engine experiences missing when accelerating in lower speeds ...also now, and since driving for a few thousand miles, f umes are entering cabin frequently and causing nausea, 'headaches and burning of mouth, lips and eyes .....all the time. My youngest granddaughter got sick and so did my oldest son just this past weekend! As far as I know , police or dealership never inspected , nor did they acknowledge it! No warning lamps appeared

I heard a ticking in the engine and noticed multiple warning lights in the dashboard. I called the GMC dealer and was told the next opening was several weeks away. I was also told that it would be OK to drive the vehicle which I did (~10 miles) and parked the truck in my driveway until I could get the truck in for a diagnostic evaluation. The service department at the GMC dealer where the vehicle was purchased identified a defective camshaft/lifter as the source of the noise and lights. The service manager recommended either an engine rebuild at their shop or purchase a replacement motor from the GMC inventory network. The serial # of the old motor is: 126852545. The serial # of the new motor is: 40208378. The cost of the new motor, replacement of required fluids and parts and labor was $12,360. 100% of the repair was paid by myself. The .pdf of the service record (RO #: 9189240) exceeds the 10 MB limit and cannot be uploaded. I have a hard copy if needed. The dealership where the vehicle was purchased and serviced is: TULLEY Buick - GMC - BMW - Mazda P.O. Box T 147 Daniel Webster Highway South Nashua, New Hampshire 03060 (603) 888-0550 www.tulley.com

I had an engine warning warning light on my dash around May 5th. A notice of reduced speed also lit up my dash while I was on the freeway. I scheduled a service for May 15th and was told the engine coolant flow control valve needed to be replaced. I was also told there was a backlog of other vehicles waiting for the same part. It has been over a month and I am still unable to drive my truck which I use for work.

My Truck has been consuming oil since new, latest documented consumption test was 1.25 quarts in 1967 miles. GM dealership said that is normal and no further diagnosis is required. GM says acceptable consumption is 1 quart per 2,000 miles. This truck has a 6.2L engine that is not under the current recall ( N252494000 ). The engine problems affect more vehicles that the current recall and should be investigated.

Dealer keeps ignoring engine knock noise states its normal , mpg is down dramatically . Shift to park , vehicle only has 34k miles and dealer does not want to repair under warranty due to vehicle being a 2021 Battery keeps draining for no reason , new battery added still does the same thing

Engine seized while at idle speed and has to be replaced. It was a catastrophic event, but not covered under the current recall for 6.2L L87 engines.

While traveling on the interstate the vehicle lost all propulsion and started to rapidly decelerate. Shortly after propulsion was lost the engine turned off completely affecting the steering and braking of the vehicle. The vehicle was towed to the GMC dealership that we purchased it from. repairs have not begun so I assume it would be available for inspection. We were traveling on a three lane interstate up a grade at 80 MPH. Had I not been able to safely get the vehicle stopped and out of traffic or had we lost control going down a grade we would not have been able to stop the vehicle and there would've potentially been a catastrophic accident most likely resulting in injury or death. No the dealership has not diagnosed the failure physically. The service writer did suggest that it sounds like the failure reported from the recall not being addressed. I did contact the dealer about the recall on Saturday May6th. At which time I was informed there was not a solution for the vehicle for my vehicle at that time. There were no warning prior to the incident. After the engine stopped operating there was a warning produced on the instrument panel that read "Engine Oil Hot" and the instrument panel no longer registered any oil pressure.

My truck has a known recall from GMC which results in total loss of propulsion. It has not failed yet, but this is dangerous to me, my family/kids, and potentially others on the road. I have made multiple attempts to speak with GMC about the issue and also my local dealer. Neither group will provide concrete information as to when they can look at/service my truck even though there is a known remedy - [XXX] I brought my car into the dealer December of 2024 for brakes and also a rattling noise since it was uncharacteristic. Noises can be indicative of this larger problem (which I know now and didn't then) but they "didn't hear a rattle" and the "condition could not be duplicated" which is patently false since it still makes the noise/has gotten worse. Since then, I have taken the following actions: - I called and spoke with the local dealer service team on 5/5 - was told since it's showing incomplete, no remedy available there was nothing they could do - Spoke with GMC on 5/5 - they directed me to the local dealership - Made an appointment online on 5/10 to get my truck serviced and to check for this problem - They immediately called me first thing on Monday 5/12 to cancel my appointment and again tell me there is nothing they can do about this issue - I have continued to express my safety concerns to both parties - I spoke to GMC today, 5/30 and was told that there is no timeline for the issue (with my VIN) even though the remedy is known - An appointment is scheduled on 6/12 with my local dealership, but if I recall status hasn't changed, they will not check for this problem INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

The truck ever since of bought it has been nothing but issues. Starting with the fuel pump issues then electrical issues and most recently the coolant flow control valve. This is my work truck and now I’m out of a truck with no loaner and the dealership has no eta.

I’m filing a complaint regarding GM Recall N232404000/N232404002, which affects the L87 6.2L V8 engine in my 2021 GMC Sierra 1500 AT4. This recall is tied to a serious defect that can cause sudden loss of propulsion due to internal engine failure. My vehicle has shown symptoms since purchase — including engine ticking, unusual noises, and low oil levels — all documented by dealership service records. GM originally instructed dealers to replace engines based on build date, which made sense given the nature of the defect. But now they’ve changed the remedy midstream. Instead of replacing potentially defective engines, they perform a PicoScope test, and if it “passes,” the only action taken is replacing the oil with a different grade. This does nothing to resolve the underlying issue. How does a manufacturer go from replacing engines due to internal failure risks to simply changing the oil and calling the problem solved? This undermines the purpose of a safety recall and places future liability on the consumer. A known internal mechanical defect cannot be fixed with an oil change, yet GM is closing out cases this way. Now I’m stuck with a vehicle I can’t fully trust — one that may still fail unexpectedly — and possibly face diminished resale or trade-in value due to an engine that other buyers will view as unreliable or patched over. GM is leaving owners with the long-term risk while clearing their books of liability. I urge the NHTSA to investigate whether this revised approach truly meets federal recall standards.

Unknown There is a recall on the this model but with different motor but when I took mine in they said it was a.manufactured defect but I was out of warranty because I purchased it cash and didn't get extended warranty now im having to replace and pay for a head and new engine over 10,000 when vehicle doesn't even have 70,000 miles it started with a engine light going on amd off for 2 weeks then it just stopped working It's too coincidental that the sister truck make n model to this had a recall for exactly what is wrong with mine

We have the 6.2 liter GM engine that has lost propultion. We are not covered in the recall and are 30,000 miles above the milage warranty, but still within the time portion of the warranty. GM payment assisitance has only offered us $1600 to help with replacing our engine. The dealership told me their warranty parts price was higher, so it really didn't offset any cost. This is our ONLY vehicle for our small appliance repair business. Our vehicle was manufactured at the plant in Canada where all the other faulty engines were manufactured. Please consider widening the recall to include our vehicle.

My GM 6.2L V8 engine has seized in less than 100K Miles. Thankfully not whilst driving and being potentially harmful to myself or others with the catastrophic failure. This problem is being widely report and continually occurring. GM is saying that I am not included in the massive recall for this, However NHTSA notes the vin range as NR and indicates incidents are still occurring. Seems to be a real lemon situation here and even bigger a letdown to uphold consumer safety.

Engine has stopped a couple of times at low speeds, Was able to restart and continue. Engine will occasionally make a "straining / Dieseling sputtering sound" when execellerating from low speeds or Stop. Transmission will make strange and strained shifts from time to time. This is reaccruing problem that comes and goes over the last approximately 2 yrs since about 9000 miles to current approx 25000 miles.

The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the low oil warning light illuminated. The vehicle was taken to the dealer but was not diagnosed or repaired. The manufacturer was made aware of the failure and referred the contact to the NHTSA Hotline for assistance. The failure mileage was approximately 67,600.

Mileage: 67,600

code P1098. Engine light comes on, power is reduced, coolant fan runs on high. Temp gauge fluctuates. This last for 20 minutes or so. The engine then returns to normal. After a few days the engine trouble light goes off. This happens every several weeks. Parts are backlogged and I understand this is a common problem with this engine. I have 64000 on it.

The contact owns a 2021 GMC Sierra 1500. The contact stated while driving at an undisclosed speed, there was an abnormal rattling sound coming from the vehicle, with several unknown warning lights illuminated. The vehicle was driven to the residence. The vehicle was taken to the dealer where it was diagnosed with cam shaft and lifter failures. The contact was informed that the cam shaft and the lifters needed to be replaced. The vehicle was not repaired. In addition, the contact stated that when the vehicle was purchased in 2020, the failure had occurred; however, the repair was covered under warranty. The manufacturer was not made aware of the failure. The failure mileage was approximately 7,000.

Mileage: 7,000

While driving vehicle started running rough and exhaust was white from tail pipes, could not accelerate and warning lights were flashing. Limped to dealership and diagnosed with a bent rod and had to tear both sides of engine apart and replace heads on both sides due to bulletin for Gmail at 7500 miles. Why is this vehicle not part of the recall to protect my investment?

While the vehicle is traveling at highway speeds it is misfiring and sputtering, giving the feeling of a hard shift. When the vehicle is idling, the engine is sputtering like it’s going to shut off. If the truck were to shut down, as it seems to be trying to do, this could be deadly at highest speeds or intersections. The vehicle has been at a dealer since January 2025. They claimed to have fixed it but upon paying over $1200 and picking it up from the dealer, the problem persisted. We had to take it back to the dealer within 5 minutes of picking it with zero repairs and no estimated time of repairs ever since. No warning lights appeared at all.

So there is recall already for the engine but I’m not part of it which is weird cause my engine has been acting weird which I’m trying to take to dealer ship but they don’t want it due to I not being in the recall list. I have the engine 6.2 LTI have an 2021 GMC Sierra Denali

The camshaft cover in pre 2021 3.0L Duramax motors is leaking oil/def internally causing oil loss. This is something GM has noted in their TSB pages but has not issued a recall over. This is a hazard to emissions, oil consumption, and the def system. Also could result in premature engine failure.

-While driving the vehicle on the highway, abruptly lost power and RPM. Check engine light, along with multiple other warning lights lit up. When parking the truck soon after, had an associated rough idle with low RPM. The truck was then towed to GMC dealership. -Multiple fuel injectors failed, starting misfiring and caused damage to the engine. Unknown if previous injectors are available, replaced at GMC dealership. The damage resulted in recommendation to replace the engine. -Engine began misfiring while traveling at highway speeds, placing me at an increased risk of loss of control of the vehicle. -The problem was reproduced, confirmed, and inspected at a GMC dealership. -No warning lights or symptoms were present prior to accident. Incident occurred abruptly.

El motor de mi camioneta falló por completo empezó a hacerle unos ruidos muy fuertes dentro del motor con solo 80,000 millas es del 2021 la compré el año pasado no llegó ni un año de uso una camioneta que supuestamente era muy buenas Estaba en el momento de lo sucedido estaba con mi mujer y mi hijo en el auto regresábamos de un restaurante acá en Miami y la camioneta se paró de pronto La camioneta fue inspeccionada por la garantía extendida la cual no asumió la reparación Luego del problema si salieron luces amarillas y rojas en la pantalla de mi camioneta

The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving 75 MPH, the vehicle lost automotive power. The contact pulled over onto the side of the road, and upon parking on the side of the road, the message "Shift to Neutral" was displayed. The contact shifted into neutral, and the vehicle was restarted. The vehicle was taken to a local dealer, and was diagnosed, and the contact was informed that no cause for the failure was found. The vehicle was not repaired. The manufacturer was notified of the failure. The approximate failure mileage was 24,453.

Mileage: 24,453

The contact owns a 2021 GMC Sierra 1500. The contact stated while driving at an undisclosed speed, the vehicle lost motive power, with several unknown warning lights illuminated. The vehicle was able to restart but went into LIMP Mode. The vehicle was towed to the dealer, where it was diagnosed that the cylinder head had failed and needed to be replaced. The vehicle was repaired. The manufacturer was made aware of the failure and referred the contact to the NHTSA Hotline for assistance. The approximate failure mileage was 43,000.

Mileage: 43,000

While driving on the highway the engine died forcing me to change lanes to cross traffic and coast to a stop on the shoulder. It was dangerous and unexpected. It would not restart so I had to have it towed. Inspection revealed the bearings had gone bad in the engine and the engine would have to be replaced. I had to wait 2 and half months for an engine.

In February of 2025 my check engine light came on while i was at work. Went to the local auto zone to have the code read and it. Right after that i drove straight to Gay Family Auto. along the way there was a jolt followed by a stall The car behind me nearly re ended me. i made it to the dealership after inspection i was told i blew a rod and had metal shavings due to an engine failure. Up to this point i had no indication of any issues or dash board warnings. i was told i needed to provide all prof of oil changes which i did. after two months i get my truck back from GMC with a new motor. The new motor is now under recall for doing the exact same thing as my old motor. GM basically took out a faulty motor replaced it with a new one in hopes nothing happens. I reached out to GM and they told me to take it to a dealership for inspection. The dealership told me they wont touch it til GMC sends a solution. im currently driving a truck that could possiably fail again

The vehicle will crank and not start. Dealership said they cannot replicate the fault. Same problem occurred after with dealership not helping. I am a US Soldier currently stationed in Germany and continue to have the same problem every 2months. It will crank and not start. The truck will start on the second attempt after cranking for about 20seconds. The continued issue can permanently damage expensive repair parts that I will not be able to afford. I know I am not the only one with the same issue as I have talked to others and have no solution for this.

The transmission is constantly whirring, rattling, and screeching.

Engine failed GM made me pay for a new one. Second engine failed due to mechanics did not change out radiator. I now have a third motor with a recall. This vehicle has cost me a lot of out of pocket expenses, I believe GM owes me for the depreciated value plus lost wages. Maybe a buy back I'm not sure.

The contact owns a 2021 GMC Sierra 1500. The contact stated while driving at slow speeds and accelerating out of the neighborhood, the vehicle experienced a loss of automotive power, with the check engine and EPS warning lights illuminated. The contact was able to drive the vehicle back to the residence. The vehicle was then towed to a local dealer where the vehicle was diagnosed, and the contact was informed that the engine had failed and needed to be replaced. The vehicle was repaired. The manufacturer was notified of the failure. The approximate failure mileage was 103,000.

Mileage: 103,000

I've noticed rough or jerky gear shifting when accelerating, rough and reduced propulsion, loss of power. Dealership repaired power torque converter but the truck continue to have the same symptoms.

We NEVER RECEIVED A RECALL NOTICE FYI . This vehicle has been serviced consistently.never an issue. Driving on [XXX] very busy! Truck literally stopped in the middle of the freeway in a very bad location. Desert. Noon. Kids with us. Could have died. Preliminary eval: engine seized, piston rod failure. Not sure the rest - we have to tow it home first. Failed while traveling. Please call for more information if needed. [XXX] [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

I was coming home after work, before I got home I stopped at the gas station to fill up my tank, after I filled up my tank I start driving home but while on my way home my truck wasn’t speed as I expected and it only goes maximum of 10mph and I was confused, I stop and check my truck see what happens but there is no sign since there was no sign I get on my truck and start driving to home, after I got home I was trying to revers parking and that’s when I realized my truck wouldn’t reverse. I thought of if it happened while I was driving on highway and my truck stopped on the middle of highway I could have lost my life. I called the dealer and the dealer told me it might be because of the engine then next day I took it to the shop and they couldn’t figure until couple days later and it took them around 2-3 weeks to replace my transmission. Luckily I had the power train warranty when I bought the vehicle and it don’t cost anything. If I didn’t have that power train warranty everything will come out of my pocket, the cost was around $6-7k.

Coolant Control Valve (ccv) on these vehicles are notorious for breaking down/ becoming non-operative. I have been waiting for a part for months.

My vehicle suddenly stopped working in the middle of an intersection. A screen notification prompted me to restart it, so I pulled over safely, as there were no other vehicles nearby. However, I worry about the potential danger if this had happened on a freeway. After waiting, I tried restarting the vehicle, but it still wouldn’t work. The next day, I received an email from Carfax about an open recall for my vehicle due to engine issues, matching the symptoms I was experiencing. I scheduled an appointment for 4/28, and had the vehicle towed to Elk Grove Buick GMC. At GMC, they couldn’t offer immediate solutions, needing to diagnose the vehicle first. This process took about four days. During this time, I was advised to contact GM, as the vehicle was affected by the recall. I submitted a case to GM on April 28th, requesting compensation for a rental or loaner vehicle, a truck for my business needs. Without it, my business operations would suffer, leading to revenue loss. The dealership’s diagnosis found the engine seized due to a failed bearing. GM contacted me about the recall, initially mentioning the lemon law and a potential buyback, which I hadn’t considered. After I expressed a desire to repair the vehicle, they contacted the dealership for more information. GM later clarified that the vehicle wasn’t covered under the recall, citing the cause and symptoms as not meeting the recall’s criteria. This seems contradictory, as a failed engine doesn’t necessarily contradict the recall. GM stated they couldn’t provide a remedy, leaving me responsible for repair costs, and noted my vehicle’s 70,000 miles exceeded the power train warranty. Recall claims dealerships will inspect and, if necessary, repair or replace the engine. It’s confusing why my vehicle isn’t covered for repairs or assistance under this recall despite the engine failure. What is the law in terms of warranty as I was under the impression that warranty status is irrelevant in an active recall vehicle.

The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving 65 - 70 MPH, there was a knocking sound coming from the vehicle and the vehicle shut off. There were unknown warning lights illuminated. The vehicle was towed to an unknown location. The local dealer was contacted. The vehicle was not diagnosed or repaired. The vehicle was taken to an independent mechanic who determined that there was a solid engine bottom and bearing failure. The contact was informed that the engine needed to be replaced. The vehicle was repaired. but the failure recurred, and the vehicle failed to start. The manufacturer was contacted and informed of the failure. The failure mileage was approximately 83,000.

Mileage: 83,000

Vehicle has less than 64,000 miles and seems to be having engine issues. ESC message with engine power reduced. Cannot even drive the vehicle any longer. Cannot get it into a shop for a month and will have to have it towed.

While driving my truck with my wife and two young boys, the truck engine completely shut off while operating it. We were stuck in the middle of the road and had to cautiously wait until we could move the vehicle out of the way. The engine locked up. Now they are trying to repair the engine with the same exact engine that is on recall and potentially put me and my family in the same dangerous position.

Tried to accelerate and heard a loud pop and the truck didn’t accelerate. Pretty much went idle in the middle of the road. The check engine light, the traction control light, and the ABS light all came on. I would press on the gas and it would rev but nothing would happen till a few seconds later the RPM’s would shoot up and you could tell it was trying to get going but didn’t very slowly and I would hear a clicking noise every time it was around the second gear. It put my children and myself in danger because traffic was heavy with vehicles going 70+mph merging into one lane. Took it to a dealership and they stated it was the the push rod and camshaft were damaged and all 16 lifters should be replaced and camshaft also. No, the vehicle has not been inspected by any of those except a car dealership and a mechanic. This problem first appeared the day it happened and continued after. Even took it to a mechanic and had all 16 lifters changed and problem still persists. Spent over $6,000 on a brand new truck and it is still undrivable because every time you get in to drive it the cylinder #2 misfires.

I had purchased a 2021 GMC Sierra equipped with the 6.2 liter motor in October of 2021. Within two weeks, my engine was experiencing problems. There was no service lights on the dash, and my truck suddenly shut off while on a busy road. I was able to coast to the side of the road, however it was a driving lane with no shoulder which made the situation dangerous. I was able to restart the engine after some time, and eventually get the vehicle off of the roadway, thankfully I got out of the driving lane without being struck by another vehicle. The truck had approximatley 1000 miles at this time and was brand new. I ended up needing a complete engine replacement due to failed crank bearings and connecting rods. I was told it was a crankshaft issue. After the complete motor replacement, sometime during the next year I was experiencing oil burning issues. On this second motor, a GM dealer had to completley rebuild the top end of the motor and install new piston rings. This is now a total of two motor failues in under 30,000 miles.

First engine blown 31,904 miles, Lifter failure. Replaced with re-manufactured engine. Second engine failure at 68,000 miles, Piston rod failure. Piston blew thru engine block and engine bay caught on fire.

I wanted to reach out to see if there is anything in addition to the lemon law. I bought a 2021 GMC Sierra with 38,000 miles on it around March of last year. There was a motor defect which was covered by the warranty. I was driving and it stopped in the middle of the road so I had to safely maneuver out of the main road. The truck was towed to my house with 45,184 miles on it, until the GMC dealership could take it in to inspect. They did take a while to get me a rental because everything was backed up. They said they could rent me out a truck due to not being their brand and that it only covers a certain amount. It got taken in by the dealership on 7/15/2024 and ended up getting the truck back repaired on 8/27. I did get the truck back and have been having it, I am just worried about it breaking down or anything of that nature. I just wanted to know if there is any further process I should do or since they repaired it there should be no issue.

Motor seized up while going around 65mph. Truck lost all power and would not start brought to dealer and they said that it was the crankshaft bearings and something with the connecting rods, the deal told me that they don’t know what to do and is waiting on GM. There is a recall for these issues but no fix. I’m just waiting for the dealer to tell me what’s next but they don’t even know.

See attached vehicle repair orders/Carfax/vehicle registration. The trucks transmission has been slipping/jerking hard since I pulled off the lot at dealer ship. Its burning oil no leaks has been doing so since the day I drove off the lot at dealership. I have asked to fix or address and problem still exist. They sold vehicle as everything was working The Left head light wasn’t working the day I drove off the lot didn’t notice until I got home I reached back out to dealer to explain and said light had a short in kept truck for almost a week said the were going to replace the head light and never did. The remote start wasn’t working the same day i purchased the truck but sold it as everything is working. I went to try it as I was getting ready to leave dealership and did nothing. Then I discovered the fog lights were missing, and dealer said oh there was never any in the truck but if you read the service paper work there was lights in truck. Took truck back to address the issues the next day or so after purchase I was told to bring truck back the following week. All the conditions still exist and I should not be having any of these issues as the sold vehicle nothing wrong. They even had an October inspection saying everything was SAT but I get in truck no fog lights and left head lamp is not working but they performed an 360 inspection….yeah no way… This truck is doing the same as my 2021 chevy Silverado but there is nothing wrong with vehicle according to dealership. Sold A Lemon if you asked me… ***Highlighted in yellow is a recall that the dealership has not done nor can they find anything on the recall**** *****Power train**** Recall date 2024-10-24 Recall no. 24V797000 General Motors, LLC (GM) is recalling certain 2020-2022 Chevrolet Silverado 1500, 2500, 3500, GMC Sierra 1500, 2500, 3500, 2021 Cadillac Escalade, Escalade ESV, Chevrolet Tahoe, Suburban, GMC Yukon, and Yukon XL vehicles equipped with diesel en

Engine power reduced, could not accelerate, fuel pump issue and was bucking the engine Went to dealer and complained as gmc not working to help me, dealer fixed issue but said no other complaints out there and car was fixed, gmc called me several times and keeps saying no issues with the vin associated. The car was fixed but I am stuck with a truck that is probably not saleable once these issues continue. This issue happened initially with 30 k on it and dealer could not find the issue and this times at 61500 happened again

was getting on the interstate whenever i hit 70 mph just heard a hard knock in the engine and truck was driving rough. the truck it self dropped to 60mph. before it occurred there was no check engine light on or anything. after i had the dash light up with engine light, brake light, stability light. about a week later took it to the dealer they said it was fuel injectors they replaced it took them about 2weeks but the problem wasn’t resolved but then stated it was the lifters which they said it almost common for this to happened. so i took it somewhere else to get replaced and they said yes it was the lifters and i needed to replace the camshaft because when the lifters go out it will damage the camshaft. all they did to diagnose my problem was hear it was ticking and the knocks also with the codes from the dealer diagnosis. after my repairs it was expensive least to say

Engine light came on, went to the dealership where I bought the truck less then two weeks prior. The Chevy dealership ran diagnostic test on it. They said it was the Engine Coolant Control Valve. This is a common problem with the 3.0 Duramax diesel engine. I belong to a group on Facebook with the same truck as mine. they are all having the same issue. We are waiting for a recall. the part is on back order and cost $300 just for the part plus labor. I bought the extended warranty and they said it did not cover this part.

Had the car since 2021. Recently started shaking while driving over 45 mph. Took the car in gmc dealership where they told me it’s an engine issue and need a brand new engine. How would I need an engine having the car for 4 years? And there is no recall?

July of 2023, lifters failed on left side of engine. Lifters replaced and cam shaft replaced. January 2025, lifters failed on right side of engine. Replaced. March 2025. Engine seized on interstate. Truck lost all power while driving, no warning signs prior. Dealership has no rental vehicles and we are not old enough to rent from a third party company so family had to drive 9 hours to our location so we wouldn’t be stranded. Three times this truck has failed us. GM is putting in a new motor as it’s still under warranty, but the new motor has no additional warranty. So basically this new motor will be warrantied for less than 7k miles. They cannot say if the new motor has the remanufactured lifters or not. So we could be facing the same exact issues. Can’t ever get ahold of anyone directly though GM.

Transmission recall was performed at a gmc dealership. Vehicle has been the the shop repeatedly since. Coolant control valve crank case position sensor new catalytic converter and dpf system. New low temp coolant loop pump. In the shop now for another low temp coolant pump that’s been shorted out. Seems to have on going electrical issues since recall was performed

The contact owns a 2021 GMC Sierra 1500. The contact stated while driving 70 MPH, several unknown warning lights illuminated, with the message to shift to neutral displayed. The contact pulled over to the right side of the road and attempted to restart the vehicle; however, the vehicle failed to respond as needed. An unknown dealer was contacted. The contact stated that the failure had occurred on several occasions. The vehicle was towed to the dealer, where it was diagnosed that the engine was damaged and needed to be replaced. The vehicle was not repaired. The manufacturer was notified of the failure and offered a monetary payment. The approximate failure mileage was 80,000.

Mileage: 80,000

The contact owns a 2021 GMC Sierra 1500. The contact stated while driving at an undisclosed speed, there was an abnormal sound coming from the engine compartment. The contact pulled over to the side of the road and discovered that the engine oil level was low. The check engine warning light was illuminated. The failure occurred on several different occasions. The vehicle was taken to a dealer, where it was diagnosed that the lifters needed to be replaced. The vehicle was repaired; however, the failure persisted. The vehicle was taken to a different dealer (Legacy Westbank Buick GMC; 3611 Lapalco Blvd, Harvey, LA 70058) to be diagnosed. The vehicle was not diagnosed or repaired. The contact was taken to a different dealer (Mossy of Picayune; 241 Frontage Rd, Picayune, MS 39466) where it was diagnosed that the engine needed to be replaced. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was approximately 27,000.

Mileage: 27,000

at 16,000 miles Bank 1 lifters fail and replaced under warranty. now at 90190 miles Bank 1 lifters have failed again this time damaging the camshaft. I have all the service records for this engine and I was verbally assured by GM in 2021 that they would cover this repair until 100,000 miles. I know from looking on Google and talking with service advisors at GM that the 6.2L ecoTec3 V8 engines are having multiple problems related to my issue. GM should be able to warranty this engine to 100,000 miles and from past experience this engine should last 200,000 with good service.

Driving 75mph towing a 24' trailer and the motor just shut down and almost caused a massive pile up on [XXX] . INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Driving on highway at approximately 70 mph and the engine completely cut off without warning. Error message on dash said put car in neutral and press the start button. After safely pulling over, the vehicle was never able to start or even crank. Towed back to the dealership. Catastrophic engine failure according to the dealership. Vehicle has the 6.2 V8 engine with known issues by GMC apparently. Only 32k miles and under warranty but dealership reports that replacement engines are on back order and they have not been able to source one.

Engine failure. Engine Locked up and truck shut down in the middle of the Freeway. Barely made it to the side of the road.

Lifter failure resulting in damage cam shafts

At cold start-up, engine (6.2) makes a metal-to-metal grinding sound for 60-90 seconds. After warm-up, a steady tick on the right side of the engine while running. I contacted GM and they said, " this was normal at start up". however, with me being a mechanical engineer, all of my school and working experience tells me anything grinding metal to metal is not good.

Engine seized and now we need a new motor

The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving 30 MPH, there was an abnormal knocking sound coming from the engine compartment, after which the vehicle lost motive power. The contact was able to pull over to the side of the road. No warning lights were illuminated. The vehicle was taken to a dealer, who determined that the engine needed to be replaced. The vehicle was repaired. The contact stated that prior to the engine failure, the transmission was replaced. The manufacturer was not notified of the failure. The failure mileage was approximately 20,000.

Mileage: 20,000

My truck was part of a GM buyback program where GM Corporation bought the truck back to fix it around Aug 7th 2023 for engine problems. I am reporting this because I do not believe that GM ever reported this to NTSHA. There are also other issues happening at the same time period that should be looked into that may or may not be coincidences. At or before 10,126 miles the truck started having engine lifter and other engine issues. General Motors will not tell me exactly what was done other than lifters according to paperwork supplied. It may have had other issues like a spun bearing but it was never disclosed. Can NTSHA please look into this and information is found, could I please get the records. I asked for the paperwork of what was done while GM owned and troubleshot all the problems. I was told that information is only available to the original owner and I could not have it. It is very frustrating when General Motors Corporate use owner’s personal data as a way to hide what was done and not have to disclose required information. I am asking for service records while General Motors owned it and the service records they did to fix it. I know that there are many more engine problems that are not documented on the vehicle summary. GM will not buy back the truck over a few lifter issues. The truck was later fixed and Art Gamblin Motorsv in Enumclaw Wa, purchased it. I am told it is fixed but have no real paperwork proving this, I was able to purchase an extended warranty just in case. There is also quite a few of battery and electronic issues that do not seem normal with the car as well. The battery was replaced at 10,126 miles at the same time as the engine issues and the battery module was replaced at 29,536 miles. At 29,875 miles and 29,965 some type of communications module and On Star module was replaced. This is the around the same time as the truck was having engine issues and was eventually bought back for what is called “engine noise”.

The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving 60 MPH, there was an abnormal knocking sound coming from the engine compartment, after which the vehicle lost motive power. The contact was able to pull over to the shoulder of the roadway, where the vehicle failed to restart. The check engine warning light was illuminated. The vehicle was taken to an independent mechanic, who determined that the engine had seized. The contact was also informed that the fuse box needed to be replaced. The vehicle was repaired, but the failure reoccurred. After investigating the failure, the contact related the failure to NHTSA Action Number: PE25001 (Engine, Engine and Engine Cooling). The manufacturer was not notified of the failure. The failure mileage was 63,000.

Mileage: 63,000

After 2 years of owning the vehicle, after every oil change, it would indicate low oil just before an oil change causing for us to add an additional a quart of oil to keep it running smoothly. We informed the service technician of the situation on multiple occasions and no further inspection was completed, and just an oil change was serviced. After a few months we noticed the engine was running rough and a white smoke coming out of the exhaust on acceleration then the check engine light came on. We brought the car to get tires replaced and to service the check engine light, the technician stated that the check engine light a failure in the catalytic converter. We brought the vehicle to the local GMC service center, where they indicated that the we required a replacement engine because of catastrophic engine failure. We reported that the check engine light was due to catalytic converter failure. The service technician ensured that the priority was the replacement of the full engine not indicating what was the main cause of engine failure stating that the catalytic converter could have led to the failure of the engine as well. We replaced the engine, and after 3 months of vehicle being in the shop the engine was replaced. Three days after receiving the vehicle, a check engine light came on. We did not drive the vehicle until we had to return it back to the service center. The service technician stated that it is due to a lack of communication from the engine to the ECU. The technician called the following Monday stating that the check engine light was due the catalytic converter. We told the technician that was the primary reason that the customer the vehicle in the first place. We asked if there was an alternative to replacing the catalytic converter since we already paid 12k for the engine replacement. We asked if they had taken apart the catalytic converter to confirm its not a sensor issue. They replied that the codes indicates its the whole converter.

I was driving 50mph when my check engine light started flashing. The engine had very little power and there was a new consistent engine knock. I took to GMC dealership and they informed me that half of the engine lifters failed and a pushrod was bent. There was no warning prior to the incident. I have had the vehicle serviced only at the dealership and have only used premium fuel. The truck has 88,000 miles.

[XXX], I PURCHASED A 2021 GMC SIERRA 1500 FROM FAULKNER CHEVROLET IN BETHLEHEM, PA. I TEST DROVE THE VEHICLE BEFORE PURCHASE AND IT SHOWED NO INDICATION OF ANY MECHANICAL ISSUES THAT I WAS ABLE TO DETECT. I WAS SHOWN BY THE DEALERSHIP THE CARFAX AND WAS INFORMED THAT THERE ARE CURRENTLY NO RECALLS FOR THE VEHICLE. I WAS LED TO BELIEVE THAT THE VEHICLE WAS IN GOOD CONDITION AND SAFE TO DRIVE AND, THEREFORE, AGREED TO PURCHASE THE VEHICLE FOR THE AFOREMENTIONED PRICE (INCLUDING TAX AND TITLE FEES). I PURCHASED THE VEHICLE WITH 60,077 MILES ON IT, AND AFTER DRIVING IT NORMALLY FOR ONLY 5 DAYS (ON [XXX]) IT BROKE DOWN AND I WAS STRANDED ON THE HIGHWAY 16 HOURS FROM HOME. I WAS ABLE TO GET THE VEHICLE TOWED AND PAID $1,200 FOR THE STARTER TO BE REPLACED, WHICH IS WHAT THE MECHANIC SUGGESTED BUT THIS ENDED UP BEING ENTIRELY UNNECESSARY AS THE REAL ISSUE WAS DUE TO A CATASTROPHIC DEFECT IN THE ENGINE. AFTER THE STARTER WAS REPLACED, I WAS DRIVING THE VEHICLE ONLY A FEW DAYS LATER (ON [XXX]) AND IT SUFFERED A CATASTROPHIC ENGINE FAILURE WHILE DRIVING 70MPH ON THE HIGHWAY. I LOST CONTROL OF THE VEHICLE AND NEARLY GOT IN A COLLISION WITH ANOTHER VEHICLE. I WAS ABLE TO GET THE VEHICLE TO THE NEAREST AUTO SHOP AND AFTER INSPECTING THE VEHICLE THEY INFORMED ME THAT THERE IS A SERIOUS ENGINE ISSUE RELATING TO A SEIZED BEARING AND THE ENGINE WILL NEED TO BE REBUILT ENTIRELY. AT THIS POINT IT HAD BEEN ONLY 12 DAYS SINCE THE PURCHASE AND THE ODEMETER READ 61,662 (1,585 MILES DRIVEN SINCE PURCHASE). DUE TO THE FAULTY VEHICLE, I WAS FORCED TO PAY TO HAVE THE VEHICLE SHIPPED FROM THE LOCATION WHERE IT BROKE DOWN TO THE DEALERSHIP WHERE I ORIGINALLY BOUGHT IT (AROUND $1,200). FAULKNER CHEVROLET KNOWINGLY SOLD ME AN UNSAFE VEHICLE THAT THEY WERE WELL AWARE HAD A DEFECTIVE 6.2L V8 ENGINE. THIS DEFECT IS CURRENTLY UNDER INVESTIGATION BY THE NHTSA AND FAULKNER CHEVROLET PURPOSEFULLY OMMITTED THIS CRUCIAL INFORMATION UNTIL AFTER THE VEHICLE WAS SOLD. CLEARLY, THIS IS AN UNETHICAL BUS INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORM

I've now had 2 engines fail catastrophically, One at 19,191 miles and the second failure at 80,661. Both are the 6.2L engine. The first had crank bearings that were black. The second I was not informed of the cause but that it was seized leaving me stranded on the roadside.

While driving the vehicle shut off in the middle of the roadway. It sat in the road till it got towed. Brought it to the dealership where it was purchased and they said the engine was blown. Themis vehicle is equipped with the 6.2 motor. It happened February 16th. The dealership confirmed the engine failed. It is siting currently at the dealership and could be available for inspection.

Engine failed and had to be replaced. GMC was absolutely no help had to bring to local gas station where i had to pay almost $12,000 to get it fixed. The truck has been in shop frequently for oil issues with this motor but GMC just jerks you around. I am in sales and need my vehicle to support my family

My Vehicle went into the dealer on January 21, 2025. My initial complaint was tapping noise, I was advised that my vehicle had collapse lifters issue several days later I was informed that they have found metal shards in the lower end and found a bad crank bearing and crank. I was told that the vehicle will need an engine replacement, and that the engine is on back order with no date of fulfilment. My vehicle has 66,700 miles I was advised was out of warranty and that GM will only cover half of the estimated cost of 11,000.00.

Subject: Complaint Regarding Recurring Engine Failure in 2021 GMC Sierra AT4 Dear National Highway Traffic Safety Administration, I am writing to formally express my concern regarding recurring engine failures in my 2021 GMC Sierra AT4 (6.2L engine). At 23,000 miles, the vehicle suffered a complete breakdown due to failure of cylinder #8, lifters, and push rods. General Motors covered the repairs at that time. However, at 97,000 miles, the exact same issue reoccurred, resulting in significant engine damage. The dealership diagnosed a misfire in cylinder #8, leading to the removal of the right cylinder head, where they found a bent push rod, spun lifter, damaged camshaft lobe, and lifter roller. The repair estimate totals $9,746, but GM has refused to cover the costs, despite us having an extended warranty purchased from the dealership. This recurring failure raises serious concerns about engine reliability and manufacturing defects in General Motors vehicles. I urge the NHTSA to investigate this issue, as multiple GMC and Chevrolet owners have reported similar problems with the 6.2L engine lifter and camshaft system. This is not just a costly repair but a potential safety hazard that GM has failed to properly address. Thank you for your attention to this matter. I appreciate any guidance or action the NHTSA can take to hold GM accountable and ensure consumer protection.

AFM lifters failed which caused cam shaft to collapse under 35k miles. Had to remove while front end to repair

The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving at approximately 80 MPH, the vehicle stalled and failed to return to normal operation. No warning light was illuminated. The vehicle was towed to be diagnosed. The contact was informed that the rod bearings needed to be replaced. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was approximately 134,000.

Mileage: 134,000

The contact owns a 2021 GMC Sierra 1500. The contact stated while driving 55 MPH, the vehicle started making a knocking sound. There were no warning lights illuminated. The contact picked up his son from school and drove the vehicle to the dealer. The contact stated that while depressing the accelerator pedal, the knocking sound became louder, and the vehicle was losing motive power. The vehicle was taken to a dealer and diagnosed with engine failure. The vehicle was not repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 58,522.

Mileage: 58,522

While driving on the highway the engine 6.2 GM seized suddenly at high speed. The truck shut off completely and left rolling without any control. I had work my way accross lanes to the breakdown lane. While doing so I was almost hit by an 18 wheel trailer truck, who luckily was able to change lanes to avoid hitting me. The reason I was almost hit was because of my low speed since I had now power or acceleration.

I purchased a new 2021 GMC Sierra Denali with a 6.2L engine on 03/05/2022. On November 10, 2022, I started the truck, and the engine seized up. The truck had 9018 miles on it and 274 engine hours. The main bearings and possibly the connecting rods bearings was the problem. On January 27, 2023, I finally got a new engine installed in my truck. I had to pay for the repairs.

Driver side lifters collapsed and push rods failed on freeway without warning at 12900 miles on truck.

On the morning of 1/19/25, my 2021 GMC Sierra 6.2L AT4 went into limp mode heading south on HWY 207 in Leavenworth, WA at approximately 60 m.p.h. Fortunately, I was able to avoid a rear end collision. I quickly turned the truck off in the middle of the road and restarted it with a CEL. When I returned home almost 180 miles away, my local mechanic diagnosed a code P0303 and cleared it. Since, the truck has continued to shutter at various speeds without throwing a code. It is currently at Haselwood GMC in Bremerton, WA being scanned, recorded, and findings set to GM waiting for resolve. I have notes, exact dates, times, call records, return voice mail messages, and dealership personnel spoken to, etc. The dealer’s lead technician and I were able to replicate the shutter on a road test together on 1/27/25 at 3 p.m. after having driven just 10 miles. During my visit on the morning of 1/30/25, the lead technician stated he has since been able to replicate the shutter seemingly getting worse. I was strongly encouraged by the service manager, service writer, and lead technician their collective “personal recommendation” was to not take the truck back. Haselwood has had the truck since 1/27/25. Still awaiting a response and resolution.

lifters in the left and right side snapped into 3 pieces. Caused engine failure happened 2 different times. All before 50,000 miles. The first time was before 30,000 miles.

Engine failure

We have had several times where we are on highway and our truck like slams on the brakes causing us to lose control. It was a recall on it and GMC fixed it and within the same week of them fixing it it happened 3 times back to back. Making my truck to force another car to steer out of my way and actually went off the highway. Thank god it was just dirt snd he didn’t get hurt or anything. But I am scared to even drive my vehicle! It starting Happening for about a year now. And it would only do it like every couple months but now it’s has done it 6 times in the last 2 months!

Engine knocking and metal in oil. Been to the dealership and even though it's under warranty they will not act on it due to no check engine light present. It's making it difficult to trust driving the vehicle anymore because of the thought of the engine shutting down without warning anytime. This complaint is documented and confirmed by a dealership. They made me pay the check out fee and recommended i keep driving the vehicle until the motor locks up.

I was notified at the dealership that my truck had metal in the oil that is causing the oil sensor pump to send a ln engine code. The fix is a new engine.

Lifter noises, error codes for misfires, lost power

Le Moteur Le 13 décembre 2024 le véhicule arrêté subitement je tente de le redémarrer et ne demarre plus à plusieurs reprises je branche un obd2 et cela indique crank sensor j'envoie le véhicule au dealer et me dise qu'il y a quelque chose dans la base et aujourd'hui ils y est encore Les pneus Certains Flan de pneu de ce véhicule sont fissures tous le tour des roues

Multiple injector and lifter failures. Occurred on 2 separate occasions. Taken to dealer the first time. Told injector failure and lifter failure. Less than a week later experienced multiple lifter failures. Taken to dealer again for repair. They only replaced some of the affected lifters, even though TSB from GM recommends replacement of all of them. Currently awaiting failure of additional components not replaced. There was no warning of either occurrence. Was only driving 45 mph on my way home the first time. The second occasion was on initial start up at Dr office. Opened a claim with GM on my own, as dealership was negligent or unwilling to contact GMC about these failures, even though I provided them with the appropriate TSB directly from GM.

We had to replace the transmission at 70,000 miles even though problems were reported to the dealer at 53,340. This repair costed $2300 on a 1 year old truck. Then we needed to replace a solenoid circuit which was not covered under warranty. We repaired this 2x (the second time covered). Then at 147,000 miles 9/24, there was a cylinder misfire which bent the push rod and collapsed lifter. This engine repair cost $8300.00 dollars. Who has to replace an engine on a truck that's 3 years old. This is a defect. Please help us. We have spent over $10,000 on repairs. We faithfully do our changes and service.

I got off work started my truck heard a few pops. As I was driving the vehicle started jerking like the brakes were being applied. Then I noticed a yellow engine light and a ESC light come on. I pulled over to check vehicle and all the lights went off. Dealer was just a few miles away. So I started back up and drove to dealer. On the way to dealer vehicle started a tapping noise. Then a new message flashed something about my steering will be affected. I got I to dealer safely. Where I left the truck for repairs.

at 8500 miles the engine had lifter go out while I was driving down the highway cause to truck to vibrate and becoming on unsteady causing me to pull over in the middle of traffic. later at 36500 miles it had another lifter go out this time I was driving home at a slower speed but still cause me to have to pull over vert fast as the vehicle became unsteady and vibrated causing all the alarm to come on. Both times the truck was fixed under warranty nut they replaced it with the same parts that are causing the problems. Soon my truck will be off warranty and this will come out of my pocket.

I purchased this vehicle new in 2021. It is an Ultimate Denali trim level with a 6.2 engine. Within the first year, the driver's side head on the engine had a massive failure with only 7,000 miles. I started up the vehicle and was parked idling briefly when several light came on along with a rough idle and some exhaust smoke. I contacted On Star, who could not diagnose the problem. The vehicle was disabled and ended up being towed to the dealer, where it was being repaired for 10 days. The lifters, valves and push rods were replace. The mechanic admitted there was an internal GM problem with the 6.2 engine. I asked for the same repair be made on the passenger side head. The GM dealer refused, knowing of the faulty factory installed parts. The polished tailpipe tips were not replace and were stained by the black exhaust. They are still stained this day. I purchased this vehicle for my retirement to tow my RV. Now, I have been reluctant to travel because of the other head letting go on me somewhere out west, operating under a work load. I know of two other people who purchased new GM vehicles with the 6.2 engine, who experienced the same failure, with around the same mileage on their vehicles.

Engine failed due to a loss of oil pressure. Rod bearing failed which cause metal to be dispersed throughout the engine causing the engine to seize from a sudden loss of oil pressure from oil pump failure. Engine was replaced in June 2024 failure happened in May 2024. While driving a system message came on DIC that stated pull over immediately to prevent engine damage and no oil pressure. I was driving uphill with cars on my right in the #2 lane. Engine shut off before I could pull over resulting in decreased braking power and a lack of steering. I almost hit 2 vehicles trying to pull over to get my family to safety on the right hand shoulder. I couldn’t pull over to the left hand shoulder as there was a guardrail in the way. When I got my vehicle pulled over the only thing that stopped my vehicle from going over the cliff was a bunch of wood chips on the right hand shoulder. From the time the warning lights came on to the time the engine shut off and seized was maybe 5 seconds. It took 31 days to replace the engine and the dealership did an inspection on the engine. There was absolutely no warning there was any problems until the lights came on. My wife and [XXX] and [XXX] were in the vehicle at the time this happened. It was so dangerous where we broke down California Highway Patrol stayed behind my vehicle with its lights on. It was also a fire hazard with the exhaust sitting on the dry bark. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

L87 engine problems. I have had failed lifters, on top of transmission issues and a current oil consumption issue where I have to add two quarts of oil (sometimes more) without any indication of low oil. I took my vehicle into the local dealership and the technician asked if I had gotten any low oil indicator and I stated no. He proceeded to tell me it had little to no oil in it. Imagine this at highway speeds and sudden engine seizure.

I received a notice of a recall for a known problem with GMC transmissions. it is very well known that these transmissions lock up and cause problems with braking and can cause the vehicle to slide off the road when the tires lock up. it also causes hard shifting, which I have experienced. GMC said they will not fix the transmission, they instead will add a device to monitor the transmission, so when the transmission locks up and causes an accident, it will let me know that it was the transmissions fault!!! How is this legal? they will let me know that their transmission caused the accident after the fact? why not fix it? typical of government to do nothing about safety... and instead make laws that allow big corporations and government to make money off of peoples deaths!

The engine blew up at 67,000 mile while driving down the road. Not sure what happened but there was no warning signs at all. The dealership said they couldn’t know for sure what happened but most likely the oil pump went bad. I have spoken with a few people that have had this same problem with the 6.2 liter engine. It needs to be looked into because this could have caused a major accident on the highway.

On memorial day weekend 2023 my truck ,2021 GMC Sierra AT4 was making a awful noise. I pulled over and vehicle died. had it towed and the warranty covered new engine replacement at 54678 miles(large deposit of metal in the oil pan). June of 2024 again, traveling out of town and pickup making terrible noise and shaking at 76651 miles. Replaced lifters in vehicle. October 11, 2024 took vehicle in for oil change, drove 25 miles and vehicle making terrible noise. Pulled over and pickup died. Had it towed to dealer and they are saying it needs a new engine. ( 87000 miles) they are saying its out of warranty. There seems to be a serious problem with this engine( 6.2) in all the research I am finding. I now have a pickup that I am still making payments on , that I cannot drive.

The contact owns a 2021 GMC Sierra 1500. The contact stated while driving 45 MPH, there was an abnormal ticking sound coming from the vehicle. The contact stated that several unknown warning lights were illuminated. The vehicle was placed on a trailer and was taken to an independent mechanic who stated that the lifter and cam shaft needed to be replaced. The local dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was contacted and referred the contact to the NHTSA Hotline to report the failure. The failure mileage was approximately 133,000.

Mileage: 133,000

Per the dealership: Lifter failure, crankshaft failure, metal shavings in the oil. Complete engine failure.

The contact's husband owns a 2021 GMC Sierra 1500. The contact stated that while her husband was driving 80 MPH, the vehicle stalled. Additionally, the "Shift to Neutral and Restart" message blinked. The vehicle was steered to the side of the road where the vehicle failed to restart. The vehicle was towed to an independent mechanic where the failure was not able to be replicated. The vehicle was then towed to the dealer where it was suspected that the crankshaft bearing had seized, putting pressure on the starter, causing a short. The contact was informed that the engine needed to be taken apart for a proper diagnostic test. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was approximately 81,000.

Mileage: 81,000

The engine locked up on the truck due to bad lifters. It has the 6.2L engine and after talking to several mechanic shops and research online this is a very common issue. GM is having to put lots of new engine in under warranty due to this issue. They need to have a recall to fix a known issue that is costing people thousands of dollars to replace the whole engine in the truck. We was driving down the hey today and with no working at all the truck died and and would not crank back over. We had the truck towed to a repair shop to find out that our truck had the same issue that lots of people are having and now it’s gonna cost us several thousand dollars to have fixed when realistically GM should be paying to fix this problem.

On the evening of 5/6/24, my husband was driving home in our 2021 GMC Sierra 1500 when the truck started to run hard, shaking, and the check engine light came on and was blinking. He pulled onto the side of the road immediately and more messages were coming across the dashboard. The truck was towed to a dealership that same night. Once the dealership assessed what was wrong, we were advised by the dealership who confirmed the lifters failed. The truck is currently still sitting at the dealership as we're waiting for the parts because we've been told multiple times that the parts are on backorder. I understand the truck is available for inspection as its been sitting on the lot since 5/6/24. This is the first time this has happened to the truck, zero prior issues. The truck has great service records and has always been properly maintained. We are currently still under the manufacturer warranty. To date, the dealership is still in possession of the truck for 90 days, and we still do not have any ETA on when the parts will arrive/truck will be fixed.

On [XXX] at approximately 3 pm I left my house and was traveling on [XXX] in Fort Mohave Arizona I was only traveling 7 miles. When I looked at the temperature in the cab was 121 degrees a few moments after the display system went black and never turned back on. I arrived at the store 4 minutes after the display shut off with no warning lights or any type of notification on my phone, I had rolled down the windows to get air in the cab to see if that would help cool down if needed. I was in the store 20 minutes. I returned to the truck turned it on and everything was normal, from there I drove back home nothing happened on my drive back the display was working. At 8 30pm I was traveling on [XXX] Driving towards a casino called Avi. I had the driver's side window halfway down when I smelled a faint plastic burn thinking it was coming from the outside because I had the window halfway down. That is when the cab of the GMC filled up with smoke that came in thru the air vents and flames started to show coming from the defrost vents and under the hood while I was driving. I had to stick my head out of the window to see where I could pull over without starting a huge brush fire. As I pulled over and the truck within seconds fully ignited into flames. Enough time to grab my belongings that I was able to save. My life was at risk by this vehicle igniting while I was driving. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the vehicle failed to accelerate as needed and made an abnormal sound. The contact assumed that the sound was coming from the transmission and the vehicle was taken to a dealer. The dealer diagnosed the vehicle and suggested that the failure might be a pulley or a rod bearing failure. The contact took the vehicle to another dealer who confirmed a rod bearing failure. The manufacturer was not made aware of the failure. The vehicle was not repaired. The failure mileage was approximately 46,000.

Mileage: 46,000

The coolant control valve is faulty and needs to be replaced. GMC and the dealership know about the issue (Bulletin No. PIP5791), but are not fixing it in a timely manner. This is a safety concern as the system will automatically reduce engine power, which is a major concern when towing and/or in mountainous terrain.

The component that has failed is the engine coolant flow control valve AC Delco part number 55516369. Unfortunately the part is still installed on the vehicle. It has been taken to a dealer and this is a known issue but no recall has been issued. The check engine comes on sometimes but not always, sometimes the pickup has plenty of power to drive and sometime it will barely pull itself, all in the same trip without shutting the ignition off. The symptoms first started in December of 2023, but were sporadic, now it is nearly everytime the pickup is started. It is extremely dangerous to drive this vehicle when it has a problem. You cannot tell if it will accelerate normally or is you will push the pedal and it does nothing. The part to repair the problem is on backorder and no release date is yet available. We have been waiting for 3 months and still no word on when this will be repaired.

I purchased this vehicle used with approx 16k miles on it. Not long after getting it - as I was driving it started dinging and then would shut off. Sometimes I’m in the fast lane going 75Mph and it’ll just shut off. The dealership can’t get it to repeat itself. They said they’ve heard of it happening before but it throws different codes. There’s no rhyme or reason to causing it to shut off, but here lately I don’t even get the warning bell. It just dies on me. As soon as i shift it to neutral and press start it’ll restart instantly. But it’s scary nonetheless, and causes me to drop speed instantly and poses a safety risk especially when I have semi’s or other vehicles close behind.

"Service parking brake" "steering assist is reduced drive with care" comments showed up on screen…check engine light on, truck shaking/ vibrating completely as if wanting to turn off this all happened while driving on the road and randomly happened…please help..very Concerned

Lifters camshaft malfunction. Known issue with 2021 GMC Sierra 20,000 miles

After having simple oil and filter, and engine and cabin filter replaced at Alpine Buick GMC in Colorado Springs, CO, I received my vehicle back and noticed a complete difference in performance. It hesitates when accelerating, stays low in every gear, and bounces, and I mean bounces hard, when shifting gears, especially slowing down. When slowing down, as it shifts to the next lower gear, it almost pushes the truck forward against me pushing the breaks. Then, when feathering to accelerate slowly, it almost bounces back up to speed, hesitating until I let off the accelerator pedal a little, and it immediately shifts to about 1000 rpm in gear. I have to push really hard for it to go up a gear, and when it does, it has lost all power. My vehicle doesn’t run right anymore after my service appt. I have brought it to my hometown dealership and they say it runs fine and nothings wrong. But there is something wrong with it.

The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the vehicle was shaking with the check engine warning light illuminated. The independent mechanic was made aware of the failure; however, the vehicle was not diagnosed or repaired. The contact stated that the independent mechanic had previously replaced the lifters, but the failure recurred. The manufacturer was not made aware of the failure. The failure mileage was approximately 20,095.

Mileage: 20,095

While driving home from work around 6 am, my car had multiple warning lights and warning messages come up all of a sudden. Immediately after that I lost my power brakes and steering and was not able to control my car at 40 mph. I was lucky the light I passed was green and there was no other traffic. I was able to bring my truck to a stop after more than a quarter mile by putting all my weight on the brake pedal. The truck was towed to the dealer and has been there ever since.

DRIVING DOWN THE HIGHWAY THE ENGINE STARTED SKIPPING AND STARTED BLOWING OUT BLACK SMOKE, AND QUIT RUNNING IN THE MIDDLE OF THE HIGHWAY. FOUND OUT THE HAD A FACTORY LIFTER DEFECT ON MY MODEL AND A SERVICE UPDATE WAS SUPPOSED TO BE DONE ON THE TRUCK CHANGING OUT THE LIFTERS HOWEVER EVEN THOUGH I HAVE GONE TO DEALERSHIP FOR ALL THE MAINTENANCE THE SERVICE HAD NEVER BEEN DONE OR TOLD TO ME. THIS COULD HAVE BEEN VERY DANGEROUS JUST ENGINE FAILURE THE SERVICE BY GMC N212353840

I was operating my vehicle in northern Minnesota with a temperature well below freezing. Vehicle warning light came on that said "turn off vehicle" which I did. When I went to start it again it would not turn over. It appeared that a large amount of oil had expelled from the vehicle. It was very dangerous as I was in a very remote area with very poor cell service and extremely cold temperatures. I couldn't even run the vehicle to stay warm. The vehicle was towed to the nearest GMC dealership where they examined the vehicle and stated that the seal of the oil filter had blown off. They further stated that the oil filter which was installed by Valvoline was the wrong size. Valvoline tested the Champion oil filter and came back with findings that the filter was the correct size and noted no damage to the filter. Either there is an unknown problem with the GM engine or the Champion oil filter. Each corporation continues to point fingers at each others product.

Less than 5 minutes after my husband and 2 children parked the car and came inside, a neighbor walking rang our doorbell to let us know there was something on fire in our driveway. We ran to the back to find his truck engulfed in flames coming from the engine. We quickly called 911 and exited the house/property. The truck continued to burn with 20-25 foot flames and very black smoke for about 40 minutes until the fire department was able to control the fire. The fire was hot enough that the entire engine was significantly burnt, the seats and steering wheel were gone, the glass shattered and melted, and the tires exploded and melted. Thankfully, everyone was out of harms way and safe through this incident. However, it has been extremely traumatic on my family and neighbors and has taken a lot of time and energy to try to deal with this. The car sat in our driveway for over 2 weeks with a very potent smell causing headaches until GM and our insurance finally investigated. There is damage to our siding, driveway, landscaping, basketball hoop, trampoline, and neighbors fence. The car was only 2 years old and scares me how quickly it went up in flames and how much worse this could have been either 3 minutes earlier or if it was parked in our garage.

2021 GMC Sierra 1500 AT4 6.2L engine, Little over 39000 miles, Purchesed May 2021. This is the second time the vehicle has had this issue. The first time was aprox 15000 miles. I reported the issue to NHTSA-ODI on 6 Dec 2021 tracking # 11442943. I was driving down the interstate I heard a rattling coming from the engine (same as I had heard with the first issue). The check engine came on I ask On Star to do a digonsotic report (see attached report). The report indicated a Fuel Management System issue detected advised to reduce vehicle speed and pay load as possible. I was told by GM certified mechanics that this issue could cause the engine to lock up and come to a complete stop on the roadway. I fill that these vehicle are unsafe to operate under these conditions and may cause serious accidents. GM has known about these issues with these vehicles for several years and has failed to correct the problem.

15000 MILES LIFTER FAILURE IN TRAFFIC HIGHWAY AT SPEED 70 MPH LOST POWER ENGINE FAILED MULTILANE HIGHWAY RUSH HOUR TRAFFIC NO WARNING FAILURE

The contact owns a 2021 GMC Sierra 1500. The contact stated that while operating the vehicle, the dashboard gauges, instrument cluster, and infotainment center malfunctioned and became inoperable. Additionally, while starting the vehicle, there was a loud cranking sound coming from the engine compartment and the vehicle would not immediately start. The vehicle was taken to the local dealer, but the cause of the failure was not yet determined. The manufacturer was notified of the failure, but no assistance was offered. The failure mileage was 100.

Mileage: 100

The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the vehicle went into Limp Mode with the check engine, DEF tank, and emission warning lights illuminated. The vehicle was taken to the dealer, and the dealer replaced several unknown sensors; however, the failure recurred. The dealer determined that the computer needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure. The failure mileage was approximately 35,000.

Mileage: 35,000

Engine lifters failure, caused ESC light to come on and check engine light and other dash lights. Lack of power from engine causing dangerous driving in traffic.

1 June 2022, while driving, started hearing a clicking noise from front end, under hood. Took to local GM dealer, Mechanic drove with me, and he heard the noise, said he would order a part and safe to drive. So, I went home. 2 June 2022 started same vehicle, a very loud banging, clicking, shuttering noise from under hood, I took back to same dealer, Dealer said collapsed valve lifter. GM service notice says for dealer to fix under warranty. Apparently, a known problem with MANY 2021 GMC 5.3 L engines. PLEASE MAKE GM RECALL THIS ISSUE FOR REPAIRDS

My truck shakes/shutters at random times. while steadily driving at constant speed and/ or shakes/shutters even more when I try to accelerate.

The contact owns a 2021 GMC Sierra 1500. The contact stated that the check engine warning light was illuminated and the vehicle failed to accelerate above 60 MPH. The contact took the vehicle to the dealer who diagnosed that the DEF tank had failed and needed to be replaced. The vehicle had not been repaired. The manufacturer was not made aware of the failure. The approximate failure mileage was 4,000.

Mileage: 4,000

The contact owns a 2021 GMC Sierra 1500. The contact stated that after starting the vehicle, the check engine light remained illuminated and the vehicle would not properly accelerate while depressing the accelerator pedal. The vehicle was taken to the local dealer who diagnosed that the engine valve lifter was faulty and needed to be replaced. The vehicle was repaired. The manufacturer was notified of the failure. The approximate failure mileage was 11,000.

Mileage: 11,000

While driving, when approaching speed of 40 mph, the engine begins to have dull shutter intermittently as though I am going over pot holes or rumble strips when I am not. Regardless of time or day or weather the truck has performed in this way. I have had it to the dealership twice for the issue. The first time they said they didn’t feel anything and unable to duplicate the problem. The second time, the vehicle was with the dealer for several days trying to determine the other issue it was there for. I requested they again try to recreate the concern. The service assistance asked if I was willing to ride with the technician to see if I could point it out for him. In scheduled a time to do so, when I arrived, the technician was not there. I reside an hour away from the dealership. Making these round trips and getting no where with support or answers. When this happens, I become extremely anxious about the safety of the truck. Also- while 4 X4 is engaged, the truck has significant shutter when going up hill, as though the transmission is going to drop. The entire truck will violently shake.

Vehicle has less than 10,000 miles. Started making a loud noise and shuddering in the engine while at speed on the highway. Made it to dealer but was concerned we were going to break down before making it safely there. Service manager strongly suspects engine lifters (he drove it briefly with me and says this is a known issue with this truck & they currently have 3 other trucks in the shop with this same problem. He said parts are a 3-4 month wait and vehicle is not driveable, will break down, but couldn’t say when - could be 10 minutes, an hour, or a day. This happened to me on 2/1/22, while out of town on vacation. An hour on the phone with GM and was passed around to 3 different individuals. GM would not provide a loaner vehicle - leaving me stranded out of state. I had to get a rental vehicle on my own, GM claims they will reimburse me for a portion of this after 6-8 weeks. GM will not tow the vehicle home to Virginia (vehicle is in NC). I had to turn in rental car once I returned home because I can’t afford to keep paying for this on my own and it’s not a truck, which I depend on. Dealer is unable to fully diagnosis and document until end of week 2/7 or early week 2/14 as they are very busy. Unacceptable on ALL levels.

8 lifters in my vehicle needed to be replaced. While driving my vehicle (12/4/21), after the auto stop feature was activated my truck experienced a lack of power and hesitation. I then turned the truck off and upon starting it was making a knocking noise. I immediately checked the oil as I wanted to make sure there was oil in the engine. I had warning lights on the dashboard and drove it about 3 miles to the dealer to be repaired. While driving it to the dealer, it did not sound right and shook. I also experienced a lack of power and was concerned for the vehicle to stall out while in traffic. The dealership informed me this is an issue with the 2021 GMC Sierra with a 5.3L V8 engine. I had seen online that GMC issued a service bulletin to have the lifters replaced in the 2021 GMC Sierra that were on the lot before they were sold (early December 2021). If this is a known issue why weren't the lifters replaced in vehicles on the road before the ones sitting on the lot. 8 lifters were replaced by the dealership but there was a shortage of parts due to the nationwide problem. There were no warning lamps, messages prior to the failure. The only symptoms I had was shaking and lack of power as indicated above after the autostop feature was activated. I then drove about 2 miles and went into a store before coming out and having the loud knocking on startup followed by warning lights and messages.

Can turn vehicle off while in gear (drive specifically). When you let off the brake, the truck acts as if it is in neutral. Discovered in my driveway when accidentally forgot to shift into park when I pulled in and pushed the stop button. Truck turned off, which would only expect if in park (or neutral), let off brake, and it began quickly rolling backwards as if it was in neutral. Fortunately the brakes were working, but had any children been riding a bike on the sidewalk or walking by, my truck may have hit them. Had I been more distracted and not noticed initially, it could have rolled into the road and hit my neighbors truck. This behavior can be reproduced every single time, and I can easily supply video.

Less than 300 miles on the vehicle and it has thrown an error code P2B60. Relating to the engine coolant flow control valve position sensor. I have taken it to my local GM service center and they cannot see me for weeks. As of this morning the check engine light has disappeared but my fuel economy has severely decreased. It seems suspicious and possibly dangerous that it showed a check engine light with a warning of reduction in engine power the night before and disappeared in the AM

Famous lifter issue in the l84 engine. Hundreds of documented complaints and current class action lawsuit. I had to stop on a busy highway and it caused unsafe passing and irritated humans.

On 11/19/2021. While on the express way our truck started sounding really bad. We drove it slower to a gm dealer in Highland MI. They said we had a misfire. And there was nothing they could do at this time. We drove a little further and it got worse. We had to stop at a rest area. After dark and in the freezing weather. We had it towed to a dealer in Frankenmuth MI. Our truck has 11,800 miles . It has a diagnostics report of Valve lifter defects left bank. Starter had to be replaced. And now gm wants to only fix to affected bank . But on the unsold trucks they will repair both banks as stated in service bulletin N212353840 . If we have one bad lifter they should all be replaced as for this not to happen again. As of 12/08 2021 it is still in the shop [XXX] Thank you INFORMATION Redacted PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6).

2021 GMC Sierra 1500 AT4 6.2L engine, Little over 15000 miles, Purchesed May 2021. Drivining down the interstate with out warning, engine starting making back fire sounding noise, with a noticeable loss of power, I requested On Star to do a vehicle diagnostics, no faults was reported, No check engine light, temp was normal, oil pressure normal. The noise was off and on at first and then remained constant. Fortunataly I was able to make it safely back to my residents. I parked the vehicle and did a scan code and it did not have any codes, I did a pending code scan and it had a P0300 code. I started the engine and the noise was louder at first and then got quiter after about 15 seconds of running the check enging light came on I shut the engine down and did another scan it gave me a P0302 code. I feel that the vehicle is unsafe to drive and could cause a accident if it locks up on the highway. I contacted GM and reported the issue, they said take it to a near by GM dealer, I told them that I felt the vehicle was unsafe to drive and they tried to contact me with road side assistance but I was unable to get anyone on the phone. I feel that GM is ingnoring a known issue and that this will result in accidents and possible loss of life.

Prior to this incident I had lifter failure on my 2021GMC SierraAt 8464 miles, I was on my way to work and I heard a loud bang and I had to pullover off the highway, my dad had to come all the way out To get the vehicle because it had major engine damage and it was on a holiday so no one would come help me.The vehicle was in the shop for over a week getting these repairs done, upon receiving vehicle it had been a week and I received service four-wheel-drive messages on the dash.Trying to use four-wheel-drive after this was a no-go every time I push the button nothing would happen it would stay in two wheel drive.After this I made an appointment with the dealership for this issue to be fixed, as I was going to get readyTo leave again with the truck having no issues other than what I’ve stated when I went to go start the truck nothing happened at all every light lit up on the dash and part of me thinks it’s an electrical issue but the Other part of me thinks the motor is locked up. Also the lights would not shut off when I turn the vehicle off so I’ll have a dead battery in the morning.

Valve lifter defects. June, 2021: 7,619 miles: left side valve lifter defect necessitating need for valve, push rod replacement on left bank of engine November, 2021: 13,171 miles: right side valve lifter defecting necessitating need for valve and push rod replacement on right side of engine

a lifter went out. While driving on a turnpike going 80 mph the engine starting knocking. The truck had to be towed to a GMC dealership where they confirmed a lifter went bad. the truck is a v8 with 8,000 miles on. the dealership advised what the problem was and replaced 4 of the 8 lifters. No warning was given, as soon as the lifter went out there were all sorts of errors that started showing up including emissions issues.

While driving on the highway my truck started to buck and had a loud engine knocking noise. Speed was greatly reduced so much so that I was going under 45 mph in a posted 65. The check engine light did not come on. While sitting on the side of the highway there was a severe engine knock only when the revs on the engine were increased. Oil pressure and cooling temps were as they should be. The next day on the way to the dealership the engine started knocking. This time the check engine light came on, speed was greatly reduced at this time. After about five miles the knocking stopped and the check engine light went out. The Dealership checked it out and stated the lifters were bad. It seems that this is a known issue with GM. I was told by the Dealership that there were two other trucks ahead of me with the same issue. Also, because this is such a prevalent issue with GM, they cannot keep up with the demand for parts. My Dealership is waiting for a head gasket. GM has known about the faulty parts for approximately two years, and they are only replacing some of the faulty, poorly made parts, hoping the other side of the engine will not develop issues and fail. I feel this is placing the driver and occupants at risk while driving down the highway and not being able to maintain posted speed limits, or just locking up and engine, and coming to an abrupt stop.

The truck has 7500 miles on it and the check engine light keeps coming on then goes back off. It is impossible to schedule service as the light goes off before it gets to dealer. The when driving the truck many times the check engine light will flash for a minute or so and then remain on steady. This is very frustrating and the dealer has found nothing. It has happened probably 10 times since the truck was new and continues now. The truck was just serviced and the dealer found nothing causing this.

Driving the car it started backfiring and then the ESC light came on and the car engine seemed to become erratic as well as steering and braking error messages and the check engine started blinking. Very scary before I got it pulled over and very thankful I wasn’t on the highway etc. I’m seeing all the issues online sounds like the supposed fixes for the 2019 models having issues aren’t solving the problem. I bought mine in April and 4 months later it’s become unreliable.

Bought GMC Sierra 1500 brand new. At approximately 2300 miles the engine light started blinking. I took it in and they said they couldn't find anything wrong with it. At 3700 miles it started again and I took it in. It has a bent push rod causing engine failure.

GM has a lifter problem that causes complete engine failure. When this happens the engine completely locks up rendering the vehicle completely shutdown. This is happening over and over in early stages of 2021 Chevrolet and GMC Vortec V-8s. Mine happened at 13000 miles on a 2021 6.2L GMC Denali, and GM is only fixing the problem partially and as I understand with the same defective product that just failed. Also it is known this failure likely will happen again as it is a design flaw. If this happens in the wrong traffic situation it will be very dangerous. I am very concerned. When my vehicle was towed to dealer they had 7 other 2021 complete engine failures just like mine waiting for repair.

The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving in inclement weather, the vehicle stalled without warning. The contact looked under the vehicle and saw that engine oil was leaking from a puncture in the oil pan. The vehicle was towed to the local dealer however, the cause of the failure was not yet determined. The manufacturer was notified of the failure. The failure mileage was 5,800.

Mileage: 5,800

This is the second time I stop at the grocery store for about 15 or 20 min, get back in the car push the start, then the truck keep cranking with no start for about 20 seconds. Then I try second time and it fires up.

5300 miles and when you accelerate it knocks and or ticks, and loss of power all lights on dash came on

THE AUTO STOP FEATURE ON MY TRUCK IS DANGEROUS! THERE IS NO WAY TO PERMANENTLY DISABLE IT. WHEN PULLING INTO TRAFFIC FROM A STOP, THERE IS A SIGNIFICANT DELAY FOR THE CAR TO RESTART AND GET MOVING! I HAVE ALMOST BEEN IN SEVERAL ACCIDENTS BECAUSE OF THIS. FORGET THE $20 IN GAS THIS JUNK MIGHT SAVE SOMEONE OVER A YEAR! IT IS DANGEROUS

Mileage: 10

RETURNED HOME AFTER SOME SHOPPING. PARKED TRUCK IN DRIVE WAY. APPROXIMATELY 5 MINUTES AFTER RETURNING HOME MY WIFE SAW TRUCK SMOKING FROM UNDER THE HOOD. WITHIN ANOTHER MINUTE OR TWO THERE WERE VISIBLE FLAMES COMING FROM THE BACK EDGE OF THE HOOD. WE CALLED 911. WITHIN 5 MINUTES THE ENTIRE FRONT END OF THE TRUCK WAS ENGULFED IN FLAMES. THE FIRE DEPARTMENT ARRIVED AND PUT OUT THE FIRE BUT THE ENTIRE FRONT AND CAB OF THE TRUCK WAS DESTROYED. FIRE INVESTIGATORS DETERMINED FIRE STARTED AT BACK OF ENGINE COMPARTMENT NEAR BATTERY. VEHICLE WAS STOPPED PARKED IN OFF CONDITION. IN MY DRIVEWAY. NO MECHANICAL PROBLEMS WERE NOTICED ON RIDE HOME AND THERE WERE NO PANEL ALERTS FOR PROBLEMS.

Mileage: 3,400

WHILE DRIVING DURING WINTER CONDITIONS WITH TEMPERATURE AT 3 DEGREES ON A RESIDENTIAL STREET WITH LIMITED TRAFFIC, THE DIESEL FUEL IN THE FUEL FILTER GELLED UP WHICH CAUSED THE VEHICLE TO DISPLAY REDUCE POWER MODE AND THEN IMMEDIATELY SHUT OFF AND WOULD NOT START. THE VEHICLE COASTED TO A STOP IN THE MIDDLE OF THE STREET WHILE IN TRAFFIC. THE OWNERS MANUAL LISTS UTILIZING TOP TIER DIESEL WHICH I DID. WHILE ADDITIVES ARE NOT NORMALLY NEEDED IN MOST STATES TO FUEL FOR FREEZING CONDITIONS EVIDENTLY THEY ARE NEEDED IN OKLAHOMA. THE FUEL FILTER HOUSING IS THE ONLY PLACE WHERE THE FUEL GELLED UP, WHICH APPEARS TO BE A THEME IN MOST GMC DIESEL TRUCKS AND DOES NOT EFFECT FUEL IN THE FUEL TANK DUE TO VOLUME. GMC HAS DONE NOTHING TO IMPROVE THE DESIGN OR INCREASE INSULATION TO THE THIN FUEL FILTER HOUSING. IF I HAD BEEN IN FAST TRAFFIC ON THE INTERSTATE IT WOULD HAVE RESULTED IN AN ACCIDENT AND POSSIBLE LOSS OF LIFE.

Mileage: 2,500

TL* THE CONTACT OWNS A 2021 GMC SIERRA 1500. THE CONTACT STATED THAT WHILE DRIVING AT 60 MPH, AN ABNORMAL NOISE APPEARED UNDER THE HOOD. WITHOUT WARNING AN EXPLOSION OCCURRED. THE CONTACT MANAGED TO VEER TO SHOULDER OF THE ROAD GET OUT THE VEHICLE TO CHECK AND SEE WHAT THE NOISE WAS. THE CONTACT NOTICED FLAMES APPEARED BY THE REAR WHEEL ON THE DRIVER SIDE. THE CONTACT GRABBED THE FIRE EXTINGUISHER AND EXTINGUISHED THE FLAMES. THE FIRE DEPARTMENT WAS CONTACTED HOWEVER NO REPORT WAS FILED. THE POLICE WERE CONTACTED BUT NO REPORT WAS FILED. THE VEHICLE WAS TOWED TO QUALITY BUICK GMC, INC (7901 LOMAS BLVD NE, ALBUQUERQUE, NM 87110 (505) 765 1300) WHERE IT WAS DIAGNOSED AND DETERMINE THE ENGINE WAS FAULTY THAT WOULD BE COVERED UNDER WARRANTIES TO REPAIR. THE VEHICLE WAS REPAIRED. HOWEVER, THE CONTACT FEELS UNSAFE DRIVING THE VEHICLE. THE MANUFACTURER WAS NOTIFIED OF THE FAILURE STARTED AND STARTED AN INVESTIGATION. THE FAILURE MILEAGE WAS APPROXIMATELY 2,800.

Mileage: 2,800

THE VEHICLE WAS BOUGHT BRAND NEW AND WAS ONLY DRIVEN FOR A WEEK. IT WAS IN MOTION ON THE FREEWAY WHEN THE ENGINE STARTED TO SOUND NOISIER THAN USUAL, LIKE THAT OF AN OLDER TRUCK. IT WAS HARD TO NOTICE ON HIGHER SPEEDS ON THE FREEWAY, BUT UPON SLOWING DOWN ON CURVES, IT GOT MORE OBVIOUS THAT SOMETHING WAS REALLY WRONG BECAUSE THE NOISE SOUNDED LIKE SOMETHING WAS LOOSE INSIDE THE ENGINE. THERE WAS NO 'CHECK ENGINE' LIGHT OR ANY OTHER WARNING LIGHTS. UPON EXITING THE FREEWAY, THE ENGINE SHUT OFF COMPLETELY WHILE IN MOTION. FORTUNATELY, I WAS ABLE TO PULL IN A PARKING LOT AND PARK IT SAFELY. THE ENGINE WOULD NOT START SAFELY AFTER THAT, AND 'CHECK ENGINE' ACTIVATED. THE VEHICLE IS CURRENTLY BEING DIAGNOSED AT A DEALERSHIP. LAST UPDATE WAS THAT THE ENGINE WAS BEING TAKEN APART COMPLETELY BECAUSE THEY SAID IT'S DEFINITELY INSIDE IT.

Mileage: 625