240D terrible vibration
 

I met another mercedes owner tonight at a local restaurant, the car he owns is a 1983 240D 4 speed. He said he is having acceleration problems so I just told him the 240's are slugs anyway. Well I took it for a test drive and there is a horrible vibration at idle, makes my 300D seem smooth as butter. Once you take off and gain some rpm, the vibration goes away but once you idle it's back. What should I look for that can be causing this? I have never felt a car vibrate this bad in my life.

Starter list
 

1.Flex Discs?
2.Motor Mounts?
3.'Last time he adjusted the Valves?
4.1st I'd loosen each injector line at the Injector capnut to see if one or more
injectors are Ill.
5.Compression?

i had that problem with a 603, it was the head gasket.

First thing I'd look at would be motor mounts. I just changed mine and it makes a huge difference ... and mine weren't even that bad. Not a terrible or expensive job, either.
A flex disc problem would be noticeable with the car in gear, not at idle.
Does the engine sound bad, or is it just bad shaking? Valve adjustment would be worth trying before fearing something worse.

The engine seems to run okay, he has never done a valve adjustment though. If its an engine mount it must be metal on metal for that kind of noise. it does drive well and seems to be okay on power but he said it takes about 30+ secs to 60mph

Change the motor mounts this will likely correct about 90% of the terrible shaking. Do a valve adjustment to take care of the remaining 10%.

When I bought my 240D it was metal on metal and, I agree, I had never felt a car shake like that. I had to drive it 175 miles home and my arms were numb by the time I got there - I kid you not!

Changed out what remained of the mounts (one was only the metal bolting plate) and it was a new car. Did a valve adjustment (all were tight) and that helped out too.

0 - 60 in 30 secs, he's doing pretty good. :D

It could be metal on metal, or really tattered ... take a peek. I've heard of people finding pretty disastrous motor mount situations. It's at least a good starting point ... if they look good, I'd turn to valve adjustment. Actually if he's never done one, he should do one or have one done anyway, even if that's not the problem.
0-60 should be in the 20s ... although I have a manual so I have a little extra unbridled power at my hands.;)

I have a friend who bought a 240D recently with a really bad vibration at idle that smoothed out with throttle. Most of the vibration was due to throttle linakges that weren't adjusted right - which led to too low idle speed.

I would do valve adjustment first. Dummy me adjusted mine wrong (used non-turbo specs:eek:) and after a few months it started shaking at idle like mad even though off idle was smooth. After recent adjustment, and several blow-out tune-ups, she is idling very nice.