CK230M 'hum' - PeachParts Mercedes-Benz Forum

EAL · #1 05-26-2010, 10:12 PM

Re 2002 C230K manual transmission, about 87K miles: I've noticed a 'hum' the sound is like running finger around Tibetan medicine bowls- and heard only by sensitive ear. At first I thought tires making sound on different road surfaces; lately only on acceleration, but as of today even off accelerator or idling when stopped, though fainter a distinct hum. Problem is cannot tell if coming from under hood/engine or under vehicle itself.

Before the hum I had a throaty exhaust sound on desceleration; but now that does not seem to be problem. Also intermittently on cold start the I guess computer activation noise which comes from center of dash is loud, grinding and long.

okay so yes I am not a mechanic

I have service appointment but would like any thoughts from folk here- primarily to not have a $$ bill as a result of trying out a number of options- and I wonder could a failing belt produce the hum?

TX76513 · #2 05-27-2010, 08:32 AM

I don't own any Tibetan medicine bowls....but going to go with: noise is still there when stopped and (guess) its the electric motor that runs the auxillary fan.

EAL · #3 05-27-2010, 10:54 AM

okay is that a 'bad' thing- can I keep driving without doing damage until the service appt in about two weeks?

TX76513 · #4 05-27-2010, 11:33 AM

Unless it would go out you shouldn't have a problem. If you want to validate the possible problem unplug the aux fan and see if the noise continues.

Part 2. If it is the aux fan just replace the fan motor. The dealership and others want to sell you the entire fan assmbly its over a $1K. Phil in parts on the forum can get you the plug and play motor. It's a simple 1hr DIY.