2022 Mercedes-Benz GLC-Class Engine Problems

My 2022 Mercedes-Benz GLC 300 (17,700 total miles) suffered a catastrophic structural engine block failure and an explosive loss of propulsion while driving at highway speeds. This occurred exactly 6 days and 183 miles after a franchised Mercedes-Benz dealership performed the official fuel pump impeller safety recall (NHTSA Campaign 23V-445).The dealership's official repair invoice documents that the technician custom-modified the recall remedy by reusing parts, explicitly stating: 'Relocated floater from old pump onto new fuel pump.' Simultaneously with the mechanical engine failure, a 'Reduce Engine Oil Level' message flashed on the dashboard, indicating severe fuel dilution from the compromised fuel system.The dealership is actively violating federal recall mandates by refusing to investigate this failed safety remedy unless I sign an open-ended financial check for a diagnostic and teardown fee. They have also revoked my substitute transportation to coerce payment. Mercedes-Benz USA Corporate Case Number 23652724 has been opened. I am requesting a federal safety investigation into this dealer's non-compliant recall remedy execution."

See attached document for complaint.

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.

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.