Eben50

My C180 (2017) makes a high-pitched whistling noise while it's parked. This starts around 20 minutes after I stopped and seems to be worse if I've used the air-con. It's loud, annoying and embarrassing and can go on for quite a while. Also, it started about a month after I bought the car and seems to be getting worse. I've found that it stops quite quickly if I open the windows, but obviously that's not a very robust solution...

The car only has 54,000 km on the clock and is still in the maintenance plan. However, the dealers say this is an engine temperature regulation mechanism and is normal...?

I have 2 problems with that explanation:
1. Why is it worse when I use the air-con?
2. Why does it stop if I open the car windows?


Has anyone else experienced this? The car is going in for it's next service soon and I need to convince the dealers to fix it, it's driving me nuts!

MJ50

moved to W205 forum...

Meins321

I do drive a C180 W205 1/2016 with same noise

It started yesterday at 84.000km and i noticed it while parking at home (hot oil/hot water, drove it 35km on the road before)

Maybe it is a failing bearing from a water pump or a tube that gets clogged? does not sound healthy or normal to me..

I ask because currently even Mercedes is loaded to 1month wait on any appointment here in the north of Germany :-/

cidtek

Sounds like a leaky sunroof and yes the AC can move enough air to cause the noise.

Check the plastic sliders that often break over time.

Have you had to replace the auxiliary battery lately? Turns out the sunroof needs to go through an open/shut synchronization with the MB star system at the dealership.