willy_manilly

Hi guys, hoping you can help me! My 2010 C250 M271 has a 30 second grinding sound on startup that actually sounds like an angle grinder. This is not timing chain rattle (as I know what that sounds like unfortunately and I can hear the pump switch off after 30 secs), this is a metal on metal mechanical grinding noise. It actually sounds like a pump impeller is running but rubbing on something. It only lasts for approx 30 seconds on cold starts.

Does the M271 turbo have a secondary air pump or auxiliary air pump that runs? If so, where is it located so I can replace it/open it up and clean it out.

Thanks!

willy_manilly

Hi there,

Any thoughts on this?