Hello to everyone. I have used a Hymerwohnmobil integrated with engine 519 CDI. The vehicle has still until Oct. 2014 warranty. When accelerating the vehicle and warm engine one hears an additional noise. It sounds as if something was rubbing or grinding. Three workshop visits at different Mercedes houses did not help. All companies have confirmed the disturbing noise but finally defined it as state of the art. Who knows the problem and can help me? I am grateful for every answer. hweinz