NHTSA complaint #11667722

Owner complaint summary

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.