One problem related to engine exhaust system has been reported for the 2005 Mercedes Benz E320. The most recently reported issues are listed below.
I own a 2005 mercedes E320 cdi (diesel). The car gives off black smoke (intermittently) and a black tar like substance (black soot) pours out of my exhaust. I have complained to mercedes and they state, "the car is operating within factory specifications. " the dealership (skyland automotive, asheville, nc) states that it is due to poor quality diesel fuel. I have considered legal action under the "nc lemon law", but would rather just have the problem solved or a return of the purchase price of the vehicle.