Hey Guys,

I have a C200 Kompressor (2001 model year).

A strange howling noise appears a moment ago after starting engine. It seems like it goes from the rear part of the car. An interesting observation: it's possible to stop it for a while by lifting up a window button. The sound is so strong, that I can hear it while driving.

Do you have any thoughts what it could be?

Thanks!

 

What happens when you have a burrito!!

 

I understand that it sounds strange, but pushing the window buttons somehow makes an influence on the problem. In the moment I do it, the sound disappears and dashboard lights become a bit darker. So probably it's an electrical issue, but why it produces noise?

 

That being the case then follow you gut feeling and lift the door covers and try to reproduce the sound!!

 

Throwing guesses around - fuel pump? With more load on the electrical system the pump might be slowing down just enough to not make the noise.

 

The common cause used to be the transmission fluid pump that shuts up after a few seconds. It was redesigned. It can be a torque converter that is worn but I'm not convinced this is what you describe.