2022 MERCEDES BENZ GLC 300 Engine Problems

The contact owns a 2022 Mercedes-Benz GLC300. The contact stated that while driving at an undisclosed speed, the accelerator pedal was depressed; however, the vehicle failed to accelerate as intended. There was a misfire coming from the engine, and the vehicle lost motive power. In addition, the check engine warning light illuminated. The vehicle was taken to the dealer, where it was diagnosed with spark plug failures, coils, and the transmission needed to be flushed. The vehicle was taken to an alternate dealer where the spark plugs and coils were replaced, and the transmission fluid was flushed. The contact stated that the failure reoccurred. The vehicle was then taken to an independent mechanic who was a Mercedes mechanic, where it was diagnosed with misfire codes in cylinders #1 and #4, leakage coming from exhaust valves in cylinders #1 and #4, low compression in cylinders #1 and #4, and there was a 75 percent leak in cylinders #1 and #4. The contact was informed that the complete head assembly needed to be replaced. The vehicle was not repaired. In addition, the contact stated that the vehicle was repaired under NHTSA Campaign Number: 23V445000 (Fuel System, Gasoline) on 11/2025. The contact stated that the failure began shortly after the recall repair was performed. The manufacturer was not made aware of the failure. The failure mileage was unknown.

The contact owns a 2022 Mercedes-Benz GLC300. The contact stated that while driving at an undisclosed speed, the accelerator pedal was depressed; however, the vehicle failed to accelerate as intended. There was a misfire coming from the engine, and the vehicle lost motive power. In addition, the check engine warning light illuminated. The vehicle was taken to the dealer, where it was diagnosed with spark plug failures, coils, and the transmission needed to be flushed. The vehicle was taken to an alternate dealer where the spark plugs and coils were replaced, and the transmission fluid was flushed. The contact stated that the failure reoccurred. The vehicle was then taken to an independent mechanic who was a Mercedes mechanic, where it was diagnosed with misfire codes in cylinders #1 and #4, leakage coming from exhaust valves in cylinders #1 and #4, low compression in cylinders #1 and #4, and there was a 75 percent leak in cylinders #1 and #4. The contact was informed that the complete head assembly needed to be replaced. The vehicle was not repaired. In addition, the contact stated that the vehicle was repaired under NHTSA Campaign Number: 23V445000 (Fuel System, Gasoline) on 11/2025. The contact stated that the failure began shortly after the recall repair was performed. The manufacturer was not made aware of the failure. The failure mileage was unknown.

Multiple loss of power incidents while driving both on surface streets and highways. Causes vehicle to loss acceleration power, vehicle must be pulled over, shut down and restarted to regain power.

Multiple loss of power incidents while driving both on surface streets and highways. Causes vehicle to loss acceleration power, vehicle must be pulled over, shut down and restarted to regain power.

Defect Summary: Since 2024, my 2022 Mercedes-Benz GLC300 has had a persistent, abnormal engine noise consistent with the sound of a 4-cylinder diesel engine, despite being gasoline-powered. The noise occurs both while idling and in motion. On several occasions, the coolant warning light illuminated while the noise persisted. The defect has worsened over time, becoming louder and more frequent. Events & Safety Risks: The dealership repeatedly claimed “no problem found” because no warning lights appeared and no scanner codes were present, ignoring my time-stamped video evidence. At one point, I was advised to drive the vehicle from Morgan Hill, CA to the dealership while making the loud noise for diagnostics — an unsafe recommendation. When the coolant warning light appeared, the service department planned only to top off coolant. I insisted on a diagnostic, which revealed a coolant hose leak. Driving with a leak could cause overheating and sudden engine failure, creating a serious safety hazard for myself, my child, and other motorists. Repair History: Multiple visits to Mercedes-Benz of San Jose (2024–2025) for the same defect. Each time, the defect was dismissed or not resolved. No meaningful repairs were performed. The issue persists today. Evidence: Time-stamped video proof of defect, full service records, and documentation of correspondence with the dealership are available. Safety Concern: This unresolved defect creates a risk of sudden engine failure or overheating while driving, potentially causing loss of control or stranding occupants in unsafe conditions.

Defect Summary: Since 2024, my 2022 Mercedes-Benz GLC300 has had a persistent, abnormal engine noise consistent with the sound of a 4-cylinder diesel engine, despite being gasoline-powered. The noise occurs both while idling and in motion. On several occasions, the coolant warning light illuminated while the noise persisted. The defect has worsened over time, becoming louder and more frequent. Events & Safety Risks: The dealership repeatedly claimed “no problem found” because no warning lights appeared and no scanner codes were present, ignoring my time-stamped video evidence. At one point, I was advised to drive the vehicle from Morgan Hill, CA to the dealership while making the loud noise for diagnostics — an unsafe recommendation. When the coolant warning light appeared, the service department planned only to top off coolant. I insisted on a diagnostic, which revealed a coolant hose leak. Driving with a leak could cause overheating and sudden engine failure, creating a serious safety hazard for myself, my child, and other motorists. Repair History: Multiple visits to Mercedes-Benz of San Jose (2024–2025) for the same defect. Each time, the defect was dismissed or not resolved. No meaningful repairs were performed. The issue persists today. Evidence: Time-stamped video proof of defect, full service records, and documentation of correspondence with the dealership are available. Safety Concern: This unresolved defect creates a risk of sudden engine failure or overheating while driving, potentially causing loss of control or stranding occupants in unsafe conditions.

My 2022 Mercedes-Benz GLC 300 has been diagnosed with a valve seat failure. This requires a full cylinder head replacement. I purchased this vehicle brand new and have driven it with care, putting approximately 60,000 mostly highway miles on it. Throughout my ownership, I have exclusively used the service at an authorized Mercedes-Benz dealership. Despite my efforts to maintain this vehicle properly, the vehicle began exhibiting misfire issues just outside of the warranty period. The check engine light would flash on and off during a misfire and it presented multiple codes. I returned to a Mercedes-Benz dealership, where I was told the issue is an internal mechanical failure, worn or leaking valve seats requiring full cylinder head replacement with an estimated repair cost of $7,800. Upon researching this issue, I've learned that Technical Service Bulletins exist for this exact failure, and other owners with M264-series engines have experienced identical symptoms and failures. This misfire could happen at anytime, requiring me to stop the vehicle almost immediately. It could cause a dangerous situation in heavy traffic areas with fast moving traffic.

My 2022 Mercedes-Benz GLC 300 has been diagnosed with a valve seat failure. This requires a full cylinder head replacement. I purchased this vehicle brand new and have driven it with care, putting approximately 60,000 mostly highway miles on it. Throughout my ownership, I have exclusively used the service at an authorized Mercedes-Benz dealership. Despite my efforts to maintain this vehicle properly, the vehicle began exhibiting misfire issues just outside of the warranty period. The check engine light would flash on and off during a misfire and it presented multiple codes. I returned to a Mercedes-Benz dealership, where I was told the issue is an internal mechanical failure, worn or leaking valve seats requiring full cylinder head replacement with an estimated repair cost of $7,800. Upon researching this issue, I've learned that Technical Service Bulletins exist for this exact failure, and other owners with M264-series engines have experienced identical symptoms and failures. This misfire could happen at anytime, requiring me to stop the vehicle almost immediately. It could cause a dangerous situation in heavy traffic areas with fast moving traffic.

While driving on the [XXX] at the speed of 10 to 15miles per hour, I noticed a smoke in the from hood on the passenger side. I felt a danger and stopped the car and got out of the car immediately along with my friend, leaving my belongings phone and other documents etc. Immediately it caught up the fire. I called 911 and reported the incident. Police and Fire engine arrived and tried to stop the fire. I have sent out an email to the dealership as the vehicle is under guaranty and i haven't got any courtesy call to know about the incident. When i tried to call them they didn't even respond to me and hung the phone. I received a call from their sales department and enquiring about if i'm looking for any other vehicle which disappointed me more. I'm in shock and would like this to be investigated as this major security concern. Here is the case# i have logged with manufacturer(Mercedes) Case#:[XXX] CASE#:[XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

While driving on the [XXX] at the speed of 10 to 15miles per hour, I noticed a smoke in the from hood on the passenger side. I felt a danger and stopped the car and got out of the car immediately along with my friend, leaving my belongings phone and other documents etc. Immediately it caught up the fire. I called 911 and reported the incident. Police and Fire engine arrived and tried to stop the fire. I have sent out an email to the dealership as the vehicle is under guaranty and i haven't got any courtesy call to know about the incident. When i tried to call them they didn't even respond to me and hung the phone. I received a call from their sales department and enquiring about if i'm looking for any other vehicle which disappointed me more. I'm in shock and would like this to be investigated as this major security concern. Here is the case# i have logged with manufacturer(Mercedes) Case#:[XXX] CASE#:[XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

when ve give gas padle want go above 20 mph and check engin light is on and car shake bad

when ve give gas padle want go above 20 mph and check engin light is on and car shake bad

The car randomly shows an empty tank of gas at the start of the day, when there was a half tank of gas remaining. I filled the gas, but the car did not register any fuel-up and kept showing empty. I took it to the dealer for repair and the fuel tank sensor was replaced under warranty a month ago. Now, this week the same issue reappeared. The car began showing no gas in the tank on a random morning last week and remained driveable for a couple of days. The gas levels reappeared corrected on day #3. Today, 4 days later, the car went back to showing zero gas, and shut off while I was driving on an expressway with my minor child in the car. All of the lights on the dash lit up, and the car stopped. It is immovable. It could have caused a severe or fatal accident and this is totally unacceptable!! This is the third time this issue appears on a brand new car that I’ve had less than a year, with 15k miles.

The car randomly shows an empty tank of gas at the start of the day, when there was a half tank of gas remaining. I filled the gas, but the car did not register any fuel-up and kept showing empty. I took it to the dealer for repair and the fuel tank sensor was replaced under warranty a month ago. Now, this week the same issue reappeared. The car began showing no gas in the tank on a random morning last week and remained driveable for a couple of days. The gas levels reappeared corrected on day #3. Today, 4 days later, the car went back to showing zero gas, and shut off while I was driving on an expressway with my minor child in the car. All of the lights on the dash lit up, and the car stopped. It is immovable. It could have caused a severe or fatal accident and this is totally unacceptable!! This is the third time this issue appears on a brand new car that I’ve had less than a year, with 15k miles.