In Reply to: Agreed, mine had (has) the same noise... posted by Austin on November 02, 2000 at 19:28:42:
The Getrag transmissions in the E30M3 are notoriously noisy and buzzy. Thus, engaging the clutch and disconnecting the engine from the tranny makes the noise go away. You will find that some buzz more than others, but generally they are fairly bulletproof tranies. The noise you are hear is nothing to be worried about.
Hi, I'm not sure if this is something to be worried about, but just wanted to ask. I have recently purchased a 1988 M3 and have noticed that their is a slight (not loud, but noticible) rattling noise that sounds like its coming from the engine. This is only noticible at idle, and goes away if I push down the clutch pedal.
If the noise goes away after you press the clutch pedal down, then it is the "they all do that" syndrome.
If it doesn't go away, it is a bad throw out bearing.
Mine had a different reaction to Red Line MTL, it made the noise worse. I've heard the same from others.