Hello,
I've bought a 230 SLK (2002 - 86.000 km) two months ago. Ever since I drive this car, I hear an annoying sound whenever I touch the accelerator. You hear it immediately after pressing the pedal and also when releasing the pedal. It's a kind of rattle sound for about one second. I wonder if this sound is proper to this engine.
I've asked a dealer the question, described the sound, and he said it's normal you hear the kompressor (he didn't hear the sound when he said this). I think it's not really normal, because it's there every time I touch or release the pedal...
Is there somebody out there with this experience??
Thanks
Kris

 

Catalyst rattle?
Can't really say without hearing.

 

I do have the same noise. I was told by MB mechanic it is normal, but then next day I went back and the other guy said it is the camshaft positioning adjuster, plus they wanted to replace engine harness -total $1200. I replaced adjuster and harness adapter myself (total about $75), but the rattling noise like stepper motor in front/side of the engine is still present. And it sounds only for about a second when accelerator is depressed from idle or released from higher rpm to idle.