I have a 85' 300D which has a lot of vibration. I realize that there are engine shocks and mounts that may cause the vibration but was wondering what else it could be. Also when you are in the cabin, it is very noisy, but as soon as you get out of the cabin you cannot hear anything but the idleing engine. I am not sure if it is exhaust, although I have inspected the exhaust system and can find no cracks or leaks, engine vibration or possible the cylinders not firing as they should. Any insight would be great

 

To confirm possible engine mounts, start engine, put into reverse with brake on, then shift into forward, also with brake on. You should feel less vibration in reverse generally, than in forward gear. I f this is the case, engine mounts are likely worn out, which is very common and likely the case!

 

I would recommend checking your fuel pump, and also your injectors.

 

Thanks for the info. I had, within the last 2 months or so, replaced the fuel pump and all injectors but will recheck them again. In regards to putting it in reverse then in drive, the vibrations are exactly the same, so I am going to take a wild guess to say the mounts are gone.

 

Well I took the Benz by the shop today, and yes, it was the engine mounts. Both were worn down, about 30 bucks a piece for the mounts at the dealer.

 

Just a follow up to the vibration situation. I just got the Benz back from the shop today, and having the mounts replaced makes a WORLD of difference. Now all I hear is the bubble of the diesel engine and my Infinity sound system.

 

Thanks for the follow up, as it will more than likely help other people in the future.

 

Just wanted to reply to this post. I read this a few months back, my '73 220D had the same problems, and I bought and installed some new mounts. What an incredible difference. Night and day. So if anyone else has a problem with bad vibrations from a diesel engine, consider changing out the engine mounts. Mine were to the point where they were almost completely separated, and they had both flattened out an inch or more. Idles smooth like butter now.

 

I just bought a 1998 E300DT which had quite a bit of cabin vibration, but I thought that may be normal for a diesel (my first diesel, what did I know). There was alot of vibration at idle in gear, reverse was pretty bouncy and even acceleration at highway speed produced an annoying passenger cabin resonance. I had the car in for some repairs and maintenance and asked the mechanic if this was normal. He said that the engine was definitely coupling vibration into the chassis and recommended engine mounts (he even offered the repair to me for no charge if the vibration wasn't fixed!)

Anyway, the new engine mounts made a HUGE difference. Now I know what a Mercedes E300DT is supposed to feel like (smooth, little or no notice of the diesel vibrations).

Additional investigation shows that the little shock absorber on the front of the engine is going bad. This damps out some of the diesel clack, clack, clack. I'll fix this eventually, but the engine mounts really did the trick.