W124 Body vibration - PeachParts Mercedes-Benz Forum

yal · #1 07-21-2003, 01:06 AM

Problem just showed up after getting of the highway. Car vibrates heavily at idle in drive, you can see the hood shaking and various things in my interior rattle. If I take the car out of drive it still vibrates visibly but not as harsh as in drive.
When the car is moving, and also when I took the car back on the highway today, I noticed that there is still a perceptible vibration and it becomes a steady hum (not audible just something felt through the car).
I checked the engine mounts and they are still 1.5 inches tall, they were replaced about a year and a half ago.

Can the transmission mount cause this kind of chassis vibration? Or should i be looking somewhere else? Maybe another mount somewhere?
Just looking for thoughts and experiences....thanks

yal · #2 07-21-2003, 04:45 PM

Just got word back - ENGINE MOUNTS

Doh! he says as he slaps his face

haasman · #3 07-21-2003, 06:41 PM

Engine mounts .... but they were just replaced 1.5 years ago? Wonder why?

Haasman

psfred · #4 07-21-2003, 06:57 PM

I have a similar problem, almost a miss, but have new plugs, wires, rotor, cap, mixture is OK by duty cycle (I've not checked the EHA yet), so suspect something fuel related like cyclical lean running or some such. Could be at bad fuel distrributor.

All plugs look pretty much the same, slight tan deposit. Milage is fine on the highway (22 or so), stinks in low speed driving.

This kind of shake will fatigue the mounts, I'd bet.

Peter

yal · #5 07-21-2003, 11:00 PM

Exactly....I have been wrestling with a bad idle for a long time. I suspect my idle control valve is shot but I haven't had the time to test it, I did clean/lube it. I've also had my engine rebuilt. Last but not least I drive over some of the worse roads in the nation with HR springs and sport shocks. My mounts have been stressed so it doesn't suprise me.
My mecahnic is going to take them out Wednesday I'll let you know what he finds.

hedpe · #6 07-21-2003, 11:03 PM

thats definately an engine mount problem, i had the same problem in my 500E

it was shaking hard

psfred · #7 07-21-2003, 11:12 PM

Yal:

I put new mounts in about four or five weeks ago -- helped quite a bit, but it still rumbles.

The only thing I can find is that #3 plug is a little darker than the rest, donno why except maybe a dribbly injector. This could make the O2 sensor think "rich" and lean out accordingly, so that it's actually running too lean with excess fuel dripping from #3. I suppose I will have to spring for new injectors soon, if I cannot find anything wrong with the fuel distributor.

I did replace all the vac lines, including the idle control valve hoses, something you might want to look into -- in my case, I think the idle mixture was set with all the leaks (I replace ALL the rubber connectors, every single one was shot!), so it ran very rich afterwards. Still thumped -- sure hope it's not the fuel distributor.....

Peter

yal · #8 07-22-2003, 10:37 AM

Peter, thats what I am worried about the fuel distb. is expensive to replace. I replaced my injectors not long ago to fix a leak down issue, throttle response was greatly improved, definately worth it.
I checked my records and the mounts are the ones I put in about 5 years ago so that makes me feel more confident.

Keep you posted.

sbourg · #9 07-23-2003, 10:02 AM

The tranny mount supports little weight, but takes torque load at the tranny output shaft. I would check it at the same time.

Steve

yal · #10 07-25-2003, 09:08 AM

Ok Update! The right side passenger mount was split or broken. It just came apart when they took it out.
The new mounts make the car idle a lot smoother. Not perfect but Night and day. The tuneup work last weekend was not in vain afterall

Tranny mount was ok thanks sbourg.