NHTSA Complaint #11450424 — 2014 MERCEDES-BENZ C300

This car has 63,792 miles on it and has been continuously garaged and well cared for. All maintenance has been done timely and by Mercedes-Benz of Tysons Corner (Virginia) since it was purchased there on 01/08/14. All required maintenance was completed as advised and the car was covered under a 7 year 75,000 mile warranty. At the recent regularly scheduled yearly maintenance service completed on 12/28/21 we were advised that the that the "rear sub-frame is beginning to rust through and has a hole on the right rear (RR) and the recommendation was the "replacement of rear sub-frame soon" at an estimated cost of $4,242.40. This car has never been in an accident. In speaking to the MB service representative about this issue, I was advised that this problem has happened to several C300's from the period 2009-2014 and that Mercedes Benz was not accepting any responsibility for the issue in the US but had issued recalls in other countries. He said Mercedes maintains that it is a "wear and tear" issue. This car has not been abused and has been well maintained. This is not an area of the country where you would expect to see this type of corrosion unless the part was defective in some manner. In researching the problem on the internet, several people write about experiencing a failure of this part although the cars were older than ours and had more mileage on them. It appears to be a safety issue should the part rust through as it could puncture the gas tank or cause the rear wheels to buckle or cause a loss of control of the auto from the auto fishtailing. I have never seen this happen to a car before and I am 75 years old and have owned a number of automobiles over the years.