NHTSA Complaint #11673376 — 2021 MERCEDES-BENZ E 350

My 2021 Mercedes-Benz E350 (VIN [XXX] ) developed a serious engine issue involving cylinder misfire and check engine light. The dealer diagnosed it as a leaking exhaust valve on cylinder 4, related to TSB LI01.30-P-072328, which documents valve seat wear in M260 engines. This is a known defect acknowledged by Mercedes in technical bulletins, and other customers in the U.S. have received warranty extensions or goodwill coverage. I was denied coverage even though this is a manufacturer defect that can lead to misfire, power loss, and potential stalling, posing a safety risk on the road. Mercedes-Benz USA refuses to cover the repair (~$7,600+), even though it relates to a factory-documented problem. I’m requesting that NHTSA investigate this engine defect, as it may qualify for a safety recall or mandatory extended warranty coverage. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)