There are 1 stored owner reports matching the powertrain & transmission leading-label group for the 2021 Mercedes-Benz C-Class in our NHTSA-sourced dataset. These are unverified consumer reports and may not reflect confirmed defects.
This group counts stored reports whose component label starts with one of this site's matching prefixes, ignoring case. Each matching report counts once within the group. Components mentioned later in the label or only in the narrative are not searched. How component counts work
Loaded 1 of 1 matching reports.
Open the full vehicle complaint log (all categories)My C300 only had about 42,000 miles and was less than 5 years old. Just after the factory warranty expired, the engine was running rough and hot, and "check engine" light illuminated. My local garage quickly diagnosed the problem as a failed cylinder head, stated that it is common with Mercedes 4-cylinder engines from about 2017, and said Mercedes may cover it since it is a "known problem" and shouldn't happen with that mileage. I was charged $7,860 by my local Mercedes dealer, and despite multiple contacts with MercedezUSA, they refuse to acknowledge this is a problem or cover the cost, although in on-line the forums some people were arbitrarily reimbursed. There should be a recall to check for this obvious defect and should be covered. This defect can cause sudden engine failure and is a significant hazard to the driving public.
Complaints are unverified consumer reports submitted to NHTSA. A high complaint count may reflect vehicle popularity, not defect severity. Data sourced from NHTSA public records.
NHTSA source checks for this vehicle year
Checks are recorded separately for each dataset, not for the whole page. Dates use UTC. A missing check date does not mean no records exist.
Vehicle import recorded: Aug 31, 2026. This is the stored import date, not confirmation that every source was successfully refreshed.