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Engine
09/04/2025
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.
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Power Train
08/24/2025
The contact owns a 2022 Mercedes-Benz GLC300. The contact stated that while driving 60 MPH, the accelerator pedal was depressed; however, the vehicle failed to accelerate as intended. The contact stated that there were several unknown warning lights illuminated before the engine seized. The vehicle was restarted; however, while driving at an undisclosed speed, the failure reoccurred. The contact started the vehicle again, and the vehicle was slowly driven to the residence. The vehicle was not diagnosed or repaired by an independent mechanic or the dealer. The manufacturer was not made aware of the failure. The failure mileage was approximately 51,519.
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Power Train, engine
10/11/2024
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 safe...
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Engine, fuel/propulsion System
12/01/2024
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 m...
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Steering
06/02/2025
The vehicle's steering wheel vibrates noticibly between speeds of 47 mph and 55 mph. This issue was once addressed with a "software update" by Mercedes Benz of Portsmouth, NH. Streering wheel vibration is a concern for any driver that rely on power steering to turn or hold the car steady. In addition it creates unnecessary panic for some drivers. This issue is brought to Mercedes Benz multiple times. I had replaced all the tires at 19,000 miles, balanced, got tires aligned by Mercedes Benz dealer and the issue persists.