2021 KIA K5 Engine Problems

The vehicle experiences severe stalling and loss of power while driving. When attempting to accelerate, the vehicle hesitates, shakes violently, and will not accelerate beyond approximately 10–20 mph. The vehicle then stalls completely and shuts off. These failures occur both after the vehicle has been parked and while actively driving. When placed in drive, the vehicle shakes aggressively and stalls. The check engine light is illuminated. The stalling has occurred multiple times in the middle of freeway traffic, creating an extreme safety hazard. My child has been in the vehicle during every occurrence. On one occasion, the vehicle shut off completely while on the freeway, placing our lives at risk and nearly resulting in a serious collision. This issue is unpredictable, persistent, and prevents safe operation of the vehicle. The vehicle has been inspected and worked on by Southwest Kia and A-Z Auto, but the defect continues to occur. I believe this is a manufacturing or design defect related to the engine or powertrain that poses a serious safety risk and should be investigated to determine whether other vehicles are affected.

Within three days of purchase, the vehicle experienced a fuel system failure requiring the gas tank to be replaced. Shortly afterward, the check-engine light illuminated, indicating additional engine or emissions problems. The failures occurred without warning and made the vehicle unsafe to drive. The engine warning has continued to appear, suggesting a recurring or unresolved malfunction. The defects create risks including fuel leakage, stalling, engine shutdown, and potential fire hazard. The safety of the driver and others on the road is put at risk because the vehicle may fail while in motion. The problem appeared immediately after purchase and continues to recur. The dealer was notified but refused to diagnose or repair the vehicle further. No manufacturer inspection has occurred because the dealership declined to provide service. The warning light first appeared within the first week of ownership and has remained intermittent. The vehicle shows signs of unstable engine operation and ongoing system malfunction. The issue has been observed by the dealer, but they declined to perform proper diagnostics or repair. The defects are persistent and pose ongoing safety concerns.

no power at all all most in a accident with it when it lost power they said it’s the turbo l paid 33,000 for this car it had 35000 miles on it has 103000 on it when it lost power

The car has a sudden loss of power but doesn't shut off. The drivers eat doesn't move towards or back and the back seat popped up for no reason whatsoever. We have taken it to the dealership and they say its not a recall but its doing the same things that others in the same year and model are doing. Why isn't this one on the list . Its paid off and haven't been able to drive it for a year now . Wasted money getting it towed to dealership and back . Ridiculous!!!!

Just minutes before entering the highway, my son and I heard a very loud popping sound that startled us, like something large hit the car or a tire exploded. I immediately pulled into a gas station checked the exterior & all 4 tires, but everything appeared intact. Shortly after, while driving on hwy during morning rush hour at 65–70 mph in the far-left lane, the check engine light illuminated & almost immediately the car lost all engine power. My speed dropped quickly with cars behind me traveling at high speeds. I had to activate hazard lights & cut across 4 lanes of traffic to the shoulder, putting myself, my child passenger, & others at serious risk of a multi-car collision. While waiting for help, I plugged in my FIXD OBD-II reader later looking over diagnostics read code P0451 – EVAP System Pressure Sensor. 8 hours after car was towed & had been parked at my home & still not starting I researched the code to learn what that means & the possible cause for & found it is all emission related issues varying in reasons as simple as a gas cap replacement. Nothing of any engine failure while driving risking the lives of drivers & others so before sending my car to a mechanic, I went and checked the gas cap in case just a simple emissions type fix that is where I observed fuel still bubbling out of the tank have photos, my daughter, & sister, as witnesses. The next day car was towed to Kia Mall of Georgia on June 26, 2025. As of August 20, 2025, the dealership has confirmed the fuel tank expanded as of now there is no resolution from Kia for fixing once this happens can likely shift car frame & could be declared totaled. Component/system failed: Fuel tank/EVAP system (pressure failure). Vehicle is available for inspection at Kia Mall of Georgia. Safety risk:Complete engine shutdown at highway speeds with child passenger on board; risk of multi-car, high-speed crash. Fuel bubbling/spitting increased fire hazard. not a recall only emissions campaign needs to change

Main wiring harness melted in my fuse box, had to pay $5000 to replace, turbo leaked into my engine and cause for the engine to blow! Hadn’t even had the car a year !! This is getting ridiculous.

My current 2021 Kia K5 FUEL TANK EXPLODED while driving. I’ve had this car for about 5 years and since driving it off the lot have experience issues with the vehicle and just a few hours ago, the fuel gas tank explode raising the back seat with passengers in the vehicle. It was extremely scary and something out of the blew. My friends and I were driving and I noticed the car engine light turn on (which was so odd to me as I keep a close eye to the car maintenance) and within 20 minutes we heard two EXTREMELY loud explosions sounds come from the car with the feeling of the car shake and rise a bit and felt as a tire exploded. I did not find this usual and we pulled over and the the seat my friend was sitting on was rose and unlatched. We then did some google searches and when looking into it, it appears there have been previous issues with this situation for other K5 Kia owners but KIA has done nothing regarding the matter. A few months ago I also went due to an internal thermostat exploding and causing the engine to overheat and smoke on the freeway and because they deemed it was not under the warranty, I left car-less for a week and a high bill. I don’t understand why I have to pay and endure these service costs when this is BASIC CAR FUNCTIONS. I do not appreciate the lack of empathy from dealer and service staff and feel unsafe and concerned for my safety for driving this vehicle. And now II have to endure the costs of being car less for 14 days per the dealer. Absurd.

On [XXX] I took my automobile, a 2021 Kia K5 to Planet KIA of Charlotte NC located at 4700 E independence Blvd. I took it there to check what caused my engine light to activate. The initial diagnosis was a bad Sensor-Differential Pressure. Planet KIA repaired the Sensor-Differential Pressure at the cost of $501.17. My extended warranty company Route 66 covered $350.28 while I covered the remaining balance of $150.89. The engine light came on again the next day and while driving back to the dealership, I experienced the car slowing down and difficult to gain speed in highway traffic. I returned the automobile to Planet Kia of Charlotte and on [XXX}, I was informed that I had a valve failure which in turn caused my gas tank to swell. On [XXX] the warranty company denied request to pay for repairs due to their policy of not covering emissions which pertained to the valve. Kia refused to fix this problem due to a service campaign recall had been performed on the vehicle before I bought it. They found no issues with the vehicle pertaining to the valve or gas tank swelling. This is clearly a manufacturer’s defect, and it should have been repaired by the manufacturer. If you can, please help. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

On Mon, Nov 18, 2025, I was driving at 60 mph with cruise on. Suddenly cruise was cancelled and check engine and low oil pressure lights came on. I pulled off road at earliest point possible. Seemed to be running ok. Drove slowly to a convenience store and turned off engine. I checked oil and it was low. When I was walking out to car after buying some oil, I saw oil under car. I called tow service and had it delivered to dealership. Upon inspection, the dealership determined the oil drain plug had fallen out and the engine needs to be replaced. The oil had been changed by an independent shop at 75085 miles. This incident happened at 78,887 miles. I feel the drain plug would have fallen out before 3002 miles if it was put in loose. This issue needs to be made into a recall with reimbursements for engine replacements and towing. If this had happened on a busy road and engine seized, there could have been a wreck trying to get off road.

While driving on my way home from work my , brakes became extremely hard to press down on and then my service engine light came on this all occurred on 7/31/2024. So the very next day I took my vehicle to a Kia dealership which was 8/1/ 2024 to find out what was causing this to happen. The technician stated that they would have to put it on a machine and run a diagnostic on it. I asked the technician while they were doing that to change the oil. I also realized that the oil light for my vehicle has NEVER came on since I purchased the car. So the technician did the diagnostic and stated that my vacuum pump had went out but he couldn’t tell me why or how this had happened. I then took the vehicle to my parents house and left it there in the garage for a few weeks to have second opinion done. I then took it to another Kia dealership and they stated there was no vacuum to the brake booster and said there was a broken camshaft and metal pieces were in the engine and the engine needed to be replaced. Again I asked what caused all of this and no one could give me an answer. I had only had the car a 1 1/2 years and don’t understand what caused all of this and I now have a car that I can no longer drive.

Engine code came on, one interior headlamp works when it wants to, climate control module is bad it has cause the relay to blow and the resistor to go out. The air turns up on the control module by itself and then your ac just stops working and then starts again as it chooses. All of these are electrical issue as stated in MANY OTHER reports. And electrical issue is unsafe it can cause fire at anytime, my car is new 2021 Kia k5 Lxs, 60k miles and now who knows when the car is going to catch fire while my baby is strapped in a car seat and no AC . RECALL before lives are took from heat stroke or possible fire. To be “luxury” it’s sad I just paid my 3rd car payment and now I can’t even drive my car. Over 100 reports on this same problem and y’all do nothing. Kia is maybe at 70k sells a year now meanwhile Toyota and other are at 300k. When my baby is insured do to this crack head wiring system I will sue someone this is ridiculous.

Car will lose power when accelerating and slow down to an almost complete stop in traffic with no pick up it will jerk as it is trying to accelerate it has happen two times in six months

When you get in the vehicle to turn it on the lights are on an everything else accept for the engine. The dashboard says the the vehicle is on, however it is not. Diagnostics shows no problems. This is on going in the New K5 community.

Bought the car used and had it in within first two weeks with 6k miles on it for warped brakes. They repaired. Now it has 68k miles on it and had all maintenance. 2nd owner and now we are told the antifreeze is going thru the turbo and into head gasket and Kia will not do anything. We were not aware the 10 yr 100,000 miles was not transferable. 6k miles out of warranty and they want us to buy a motor. This car has always been maintained and should not need a motor with only 68k miles. The optima’s had the same issue as we also have an optima which was covered due to recall. This should be looked at. The dealership charged us 200 for diagnostics and said too bad you pay for it.

Car thermostat failure, car overheats and only 89000 miles

One day I was driving my car when suddenly I heard a loud explosion sound from the back. I continued to drive the car until I could pull over to inspect the car. In the midst of pulling the car over I began smelling a strong odor of gas in the cabin of the car. Prior to stopping the car started skipping and missing badly. I pulled over checked the car and discovered something malfunctioned and caused the rear seat to pop up and be bent from the frame. I proceeded to look under the seat and saw where what appeared to be the fuel pump almost popped out, the bracket above the fuel pump was broken and popped up from the explosion, the seat would not go back in place. I looked at the gas hand I went from 3/4 tank of gas to E in less than a few miles. The exhaust also sounds like something blew or came apart the car runs very loud and you can hear the car sounding like the exhaust have a hole. After the sequence of events the engine light never came on. This is huge life safety problem that should have never happened.

Does not always shift like it is supposed to

Vehicle engine shut off while driving down the highway. Traveling on 74 and while still in drive the engine abruptly shut off. Vehicle was started again and then it again shut off a couple miles down the road. When the vehicle was started a 3rd time it immediately went into limp mode. I was stuck on the side of the highway with vehicles going 70MPH around me. On my way to the dealership the car shut off multiple times potentially killing me multiple times. After 60 days at the dealership they said they fixed the problem. I drove the car 4 miles and it shut off on me on the highway again. I had a car almost crash into me along with trying to start the car and get off to a safe location. I still do not know what is going wrong with the vehicle but this could of killed me and others..... this needs to be addressed along with the fact they gave me the vehicle back just for it to do it again.

VEHICLE WAS STOPPED A RED LIGHT ON A CITY STREET WHEN SUDDENLY CUT OFF. SMOKE BEGAN TO POUR OUT FROM UNDER THE HOOD. LESS THAN 1 MINUTE LATER THE VEHICLE WAS FULLY INVOLVED UNDER THE HOOD OF CAR. CAR WAS A TOTAL LOSS. VEHICLE HAD JUST BEEN DRIVEN APPROXIMATELY 25 MILES (ALL HIGHWAY) FROM HOME TOWARDS WORK WHEN INCIDENT OCCURRED.

Mileage: 3,000

WHILE I WAS DRIVING ON THE INTERSTATE, I HEARD AND ABNORMAL ABOUT OF NOISE COMING FROM THE ENGINE BAY AS WELL AS A SCRATCH WHILE I WAS DRIVING. THIS HAPPENED ON MARCH 26, 2021 AT 10PM. ON MARCH 29, 2022 I TOOK IT TO THE DEALER SHIP AND I WAS NOTIFIED THAT MY ENGINE COVER CAME OFF AND WAS THE CAUSE OF THE NOISE. THERE'S DAMAGE TO MY DRIVER SIDE FENDER, RUBBING TO THE WHEEL/TIRE AND MY FOG LIGHT HOUSING IS HANGING.

Mileage: 3,285

WHILE DRIVING THE VEHICLE AND AFTER IT IS PARKED AND ENGINE IS TURNED OFF THE COOLING SYSTEM ( COOLANT RESERVOIR ON UPPER RIGHT SIDE OF ENGINE ARE) ALLOWS ANTIFREEZE VAPORS AND HIGH PRESSURE TO ESCAPE INTO ENGINE AREA. WHEN PARKING IN A GARAGE THERE IS A VERY STRONG SMELL OF COOLANT. DEALER HAS VERIFIED THAT THE RADIATOR CAP APPEARS TO ACT AS A VENT ALLOWING VAPORS TO ESCAPE THE SYSTEM.

Mileage: 75