2021 MERCEDES-BENZ GLC 300 Complaints

Our 2021 Mercedes is 4 years old and had the engine light come on. The vehicle has always been maintenance by Mercedes and well taken care of. The engine had a Cylinder Head Failure which resulted in a $7600 repair for a 4 year old vehicle. Mercedes refused to offer a good will repair. This is A major issue reported in 2015–2016 M274 engine which can lead to catastrophic engine failure 1. These failures often result in loss of power, strange engine noises, and in severe cases, engine seizure. The damage can extend to the cylinder head, especially if broken piston fragments impact the combustion chamber. This is a major risk for all owners of 4 cylinder Mercedes. Mercedes of Canada has already issued an extended warranty but owners of US Mercedes vehicles are left on the hook for the bill and risking their lives while this is a known issue.

I seen a recall for certain 2021 GLC 300 vehicles for moisture in right side headlamp, causing headlamp to blow (go out). This happened on my 2021 GLC 300. Same moisture issue, same year, same model, however, my vin number does not show that it has a recall. I believe this safety issue needs to be expanded to include my vehicle. Same issue, same year, same make and same model

The contact owns a 2021 Mercedes-Benz GLC300. The contact stated that there was condensation inside the front passenger’s side headlight housing after it had rained. The contact then stated that while driving at night, the passenger’s side headlight failed to operate as needed. There was no warning light illuminated. The dealer was notified of the failure, and the contact was informed that the vehicle was not included in NHTSA Campaign Number: 22V261000 (Exterior Lighting); and the contact was provided an estimate for the repair. The vehicle was not repaired. The manufacturer was notified of the failure but offered no assistance. The failure mileage was approximately 92,700.

On [XXX] my GLC 300 AWD while driving back from work started shaking, went into limp mode, engine started misfiring and check engine light came on. Pulled over into a parking and called Mercedes-Benz road side assistance, they sent a tow truck and the car was towed to the Mercedes-Benz of Oklahoma City. The service department informed us of cylinder head failure and told SUV needs cylinder head replacement that would be covered under the extended Mercedes warranty. As of March 22, 2025 SUV is still at the Mercedes dealer and not fixed. This is the second time in past few months GLC went into limp mode and lost power and acceleration while on road, it was towed to the Mercedes dealer. They initially said they couldn't find anything wrong but later performed an update of engine management software on the recommendation of Mercedes-Benz USA. Car was fixed at that time. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

While driving my vehicle on March 3, 2025 the check engine light came on. Additionally my vehicle began to shake. I was scheduled for a service appointment on March 5, 2025 and told the service department the check engine light need to be addressed. Upon inspection, it was determine the cylinder head needed to be replaced due to a leaking exhaust valve. Estimated cost of $8,818.12. I was devastated and disappointed we had a 2020 Mercedes GLC 300 had the EXACT SAME PROBLEM in 2023. The cost to repair was estimated at $9000!!! How coincidental is that 2 vehicles in the same family have the same problem on newer model vehicles!!!! After researching the web, we discovered that the warranty was extended on the M260 cylinder head however my engine is M264 engine just for RWD cars. Mercedes will not cover it even though this is the 2nd GLC 300 that WE have reported the problem with the cylinder head. They would not even replace the part and we pay for the labor. I am truly disappointed and most likely never be a Mercedes purchaser again. Especially since they cannot stand behind their product. The cylinder head failed and caused my daughter to be placed in harm's way by beginning shaking while driving. This could have caused an accident and put others at risk. This problem has been confirmed by 3 different dealerships on 2 different vehicles( 2020 and 2021 Mercedes GLC 300). It has been inspected by the dealership that confirms it is leaking and needs to be replaced and confirmd it was not the negligence of the driver. There were no warning signs besides the check engine light coming on.

High beam can't auto dim Fuel pump fail to operate, misfires, and shut down while driving

While slowly backing out of the driveway and without contacting anything at all, the rear window completely shattered. The window has never been hit by anything and had no defects yet it completely shattered so clearly reflects a manufacturing defect of some sort that is incredibly dangerous to passengers or other vehicles, since it happens without warning and without the necessity of an impact of any kind.

Mercedes App displays low battery alert. Brought to dealer who stated Mercedes told them (dealer) to inform anyone coming in with this issue to just disregard the alert in the app. Had the battery checked anyway. At the conclusion was told I had to “drive the car longer so the battery would recharge”.

Driving short distance home when the bottom of Mercedes GLC 300 caught fire without warning or notification. I was unaware when a good Samaritan screamed out your car is on fire. Pulled over and she helped me out. Seconds later the car exploded into flames and the car was demolished.

The contact owns a 2021 Mercedes-Benz GLC300. The contact stated that while driving at low speeds, the vehicle lost motive power struggling to produce enough power to propel itself on a slight incline. The check engine warning light was illuminated. The vehicle was taken to an independent mechanic, who diagnosed a failure with the fuel pump. The vehicle was not repaired. The vehicle was then towed to the dealer, who confirmed the diagnosis. The vehicle was not repaired. After investigating the failure, the contact related the failure to NHTSA campaign 23V880000 (Fuel System, Gasoline), but the VIN was not included. The manufacturer was notified of the failure; a case was opened, and the contact was referred to the NHTSA hotline for assistance. The failure mileage was 80,000.