Duckmoore

2007 SL 550 R230 With 100,000 miles. It has a vibration/shaking noise at idle or in traffic. It only happens when the car is hot. The ironic thing it only happens every now and than. The a/c can be on or off. . All spark plugs are good and air filter. I purchased the car from Florida and drove to New Orleans with no problems. My wife is afraid it will stop on her especially in traffic. Your in put would be appreciated.

Rudeney

My guess would be engine mounts. They are fluid-filled, so it may take heat to get them to the point that they are viscous enough to allow the vibrations.

bobterry99

It this is not a constant, then it probably is not engine mounts. I have no concept of what a "vibration/shaking" noise sounds like.

You can check engine mount condition by revving the engine with your foot on the brake pedal and transmission in "D" and "R". Have the hood up and watch for exaggerated engine movements to the left and right.

If you have Star Diagnosis, I'd have a look at "smooth running" values for your engine. I presume these are available for your M273 engine as they are with the M113. If you haven't got Star Diagnosis, then spend $350 or less to put one together.

Duckmoore

I’ve had that check already and they were in good shape. Maybe you I can add that it’s as the car is going to shut off feel. As for example to low of an idle feel. What I have describe is not all the time and only with the car is idle or stand still with foot on brake. Hope I’m clear.

Rudeney

So RPM actually drops?

Blazeracer

A u-joints on its way out could be a source of vibration also. There are six of them I believe. Two each on the drive shaft and half shafts. Plus that big rubber thing by the differential could have a crack or something. Transmission mount can be another vibration source.

Duckmoore

Never thought about that. I will get my tech to check that out? Thanks

bobterry99

If he'll do it at no charge, why not? Otherwise, how plausible is it to you that wear in the driveline would cause vibrations while the vehicle is stationary with the engine idling?

Blazeracer

Aaaah, I didn’t see that it does it at idle. That rules out a u joint.

bellwilliam

on my engine mounts, one of them was bad (causing vibration). but there was no way to examine it visually, the engine mount looked good with no leaks.

not saying this is your case, but I wonder how your tech checked it?

sdwtchlvr

Have you tried pulling any codes? I had a misfire (which should throw a code) that felt very similar. Shaking, feeling like the car was going to die.