New Noise from 3 to 10mph in 2000 C230

[N41EF]

Now that I replaced both engine mounts on the car it is whisper quiet at idle, and stopped in drive or reverse. The right side mount had colapsed and in drive was letting the exhaust hit causing a metal on metal noise that drowned out just about everything. Now that it's quiet i can hear another noise.

As you begin to roll from a stop at about 3mph I can hear a clicking noise that soulnds like the a/c compressor cycling or something similar, but when you get to about 10mph, it goes silent again. Also does it in reverse. Turned of the ESP and it does it. It sould like it is coming from the left front somewhere, and does it every time you slow down to a stop, or take off. It's probably been doing it the whole time, I just couldn't hear it with the engine mount bad.

Any Ideas?

[ILUVMILS]

Diagnosing noises over the internet isn't easy, but I'll try.

I recently had a similar issue in my shop, also on a 2000 C230. It turned out to be the A/C compressor knocking at times. Try running it with the A/C off and see if anything changes. Another common underhood rattle on M111 equipped MB's is the cam advance mechanism. This is a fairly common problem, but before replacing it (not exactly a DIY job) disconnect it and see if the noise goes away.

[mbdoc]

Another common noise on M111's is the belt tensioner..

IF your belt tensioner DOESN'T have a shock absorber it NEEDS to have 1 retro-fitted.