White_Knuckles

With colder weather, I am greeted with a new vibration, only at idle, enhanced by placing it in gear. You feel it in the wheel and door armrest. A fast vibro thing not an unstable idle with the tach drifting.

Searches suggest engine mounts as ignition is fine (no missing). I'd like to test for motor mount failure but not sure how. I read you can "raise the engine" and the mounts shouldn't allow rise if they're good. Uh, where do you jack? The whole engine at once or under each mount?

Others claim they can tell by how flat they are. Hmmmm, flatness? Gosh, I don't have a baseline of a chubby one as a guide. One post says rev the engine and it shouldn't pitch more than an inch. Sounds interesting but would that indicate too much lift or too much collapse? Arrrrrgh!

Would there be any quantifiable tips with supporting information out there?

arno

If the idle changes when shifting to park/nuetral/reverse the most likely cause
is the motor mounts.

a'

ps2cho

Easiest way is to take off the air assembly then put a block of wood under the engine and jack it up. You can do it all at once. The mounts should be visibly bad though if you look. Check for any leaks in the mounts as Mercedes has liquid inside of them.

White_Knuckles

Ps2co! I thought of your primary post when the idle went from glass to vibro-mode. Eeeeek not the P-curse!

I like the visual inspection, checking for spooge. The jacking part still bugs me. Why remove the "air assembly"? You mean the upper intake plastics? I don't think anything will hit the hood with M104 profile. I'm wondering where a good jack point is? Got the wood thing but the center of the engine is the dread oil pan - no jack zone.

I'm guessing the best point of view is from under the car. I'll check it out tomorrow.

Thanks all.