After discovering that my (1979 W123 300D) diesel injector pump predates the advent of pumps incorporating a rack dampener adjustment, I was confronted with what to do about the deep, coarse vibration that was occurring at idle. Adjusting the idle speed did not help, as the engine then idled too fast. Following a posting here, I went ahead and changed the inline and canister fuel filters. That made a remarkable difference. I was then able to set the idle down to where it should be. I am still not satisfied with the level of vibration that remains at idle. I am beginning to question whether my Mercedes shop actually change the engine mount vibration absorbers when they did a complete engine rebuild earlier this year. Changing engine mounts have always quieted my engines down in the past. For instance, my last 300D, I had adjusted so that it was so buttery smooth at idle, it was a pleasure to behold. Then again, that was a four-cylinder diesel, whereas the current one is a five-cylinder OM617.
Does anyone have an opinion as to whether or not this engine might smooth out better once it is fully broken in? The currently has only around 1,500 miles on it.
Thanks!