One problem related to engine grinding noise has been reported for the 2013 Mercedes Benz C250. The most recently reported issues are listed below.
At 46,000 miles my Mercedes Benz C250 began hesitating to start and then after starting made a slight grinding noise for 3 to 4 seconds. After the car had hesitated to start for several days the engine light then came on. When taken in for repair I was told the cam sensor as well as the cam gears needed to be replaced. I have done all scheduled maintenance on this vehicle and am a very conservative driver, as this car has very low miles for being a 2013 model. After a brief online search I found countless complaints from other consumers that had the exact same problem with their Mercedes Benz C250. If the vehicle is out of warranty the dealerships are unwilling to perform this work at any kind of discount because a formal recall has never been made for this engine model. This repair ranges in price from $4,000 to $5,000. This seems like an issue that urgently needs to be looked into as many consumers are being left to pay this excessive bill for an issue that I believe Mercedes Benz knows is a systemic problem with the engine in the C250 model.