idle shake with A/C? - PeachParts Mercedes-Benz Forum

JHZR2 · #1 05-02-2004, 01:04 PM

Hi,

I have had a bit of a shake at idle. It seems to be getting more and more common, although it never has totally gone away, even when I had the dealer replace the mounts. it seems to be more occurrent as the engine is warming up, but definitely will shake after a fast run, when sitting at a stoplight, etc., where there wasnt much time between fast rpm and idle.

It doesnt matter whether Im in drive, neutral or park, itll shake.

I have had two different independent techs look at the engine and neither said therre was an issue with the mounts. when the engine is off, I can yank the engine every which way and not be able to get it to budge.

I just adjusted the valves, none were too tight, a bunch were a little bit loose (I did it outside last winter, I guess that was the problem), no change in the shaking.

One thing that I have noticed though is that if the AC is on, the shake will be much less severe if at all. also, if I take it up just a few RPM, the whole engine will smooth out. However, it idles at the speed that is specified on the card in the engine bay.

Could the loads on the engine actually keep it from shaking? Would this indicate that something attached to the engine is not correct? My engine mounts are less than 2 yrs/50k old, and they are dealer installed. I cant imagine they are bad.

Sorry to beat the shaky idle bit to death with another thread, but I havent seen any on the correlation between an engine load and the idle smoothness.

Thanks,

JMH