Body & structure
Filed Jul 18, 2026
The sunroof panel being cracked on this car is a well known and documented issue. There have been several recalls for it just not on my specific model. Yet I’m just like them, stuck with a broken in half sunroof panel that let water seep in and ruin my sunroof twice now, and the only fix is to pay $4500. This is insanely high for the small panel I’m talking about.
- NHTSA ID
- 11751245
- Incident
- Mar 11, 2025
I am reporting a structural failure of the rear subframe due to corrosion on my 2015 Mercedes-Benz C300 4MATIC. The failure was diagnosed by an authorized Mercedes-Benz dealer, who confirmed that the rear subframe has corroded and broken, compromising the structural integrity of the vehicle. This is not cosmetic rust. The subframe is a load-bearing structural component, and its failure creates a serious safety risk, including potential loss of vehicle control. I have been advised that the vehicle may be unsafe to operate in its current condition. The vehicle has approximately 143,000 miles and has been registered and operated in Connecticut, a salt-use state. However, this level of corrosion leading to structural failure of a major suspension component is premature and not consistent with normal wear and tear, even in such environments. I contacted Mercedes-Benz USA and escalated the matter to an Executive Referral Manager. Mercedes-Benz acknowledged the seriousness of the issue but declined to provide any repair assistance, stating that my vehicle falls outside of warranty extension and goodwill parameters. Mercedes-Benz did not dispute the nature of the failure or its safety implications, but refused to address the issue based solely on internal policy criteria such as age and mileage. A rear subframe supports critical suspension components. Corrosion leading to structural breakage can result in instability, misalignment, or failure of suspension components while driving, increasing the risk of a crash. This issue appears to be consistent with known reports of rear subframe corrosion in similar Mercedes-Benz vehicles, raising concern about a broader safety defect. The failure was identified during inspection, and repair costs are estimated at approximately $5,000–$6,000. I am submitting this complaint due to the safety risk posed by structural failure and the manufacturer’s refusal to address the issue.
- NHTSA ID
- 11724925
- Incident
- Jan 19, 2026