young

but i notice that it makes a relatively high pitched noise for a while before it settles down. is that normal? maybe i'll record the sound so you can hear it, mbtech?

Darkmann

Sounds like you have 01 or 00 model year. The noise you describe isn't normal since the comporessor isn't running in heat mode. The only other possibility is the fan. Try running the A/C and check if the noise persists. Then run system (A/C and Heat)in both auto and manual mode? Run in both recirc and none recirc mode. If the noise persists, have the system checked - it's probably the fan. If it only happens in one mode, I'll start by making sure that t the vents are not blocked by dry leaves or the like. Hopefully MBTech will give you more info.

Darkmann

I just posted below. If you run the tests I prescribed one after the other, the problem may not manifest itself - If it's a friction lubrication problem, you have to give it time to "unsettle" down in order for the noise to reoccur. Keep a good 1-2 Hrs between tests.

young

i have a 2002 c230k coupe. i'll have to try those tests more, but i'm pretty sure it only happens when its generating heat in the morning and not the AC. i'll check for leaves tomorrow morning - actually, we have a ton of trees here and they've just all fallen.