Hi guys!

First post here. I'm about to take my car to nearby Volvo shop but wanted to see if you guys might know what's going on with my car.

My car is a 2005 S60 2.5T with about 50k miles. Lately it has developed a buzzing/humming noise whenever the car is running. I've listened under the hood and it seems to be coming from behind the driver's side headlight in the engine bay.

The pitch changes momentarily if something draws a lot of current, like turning on the fan or jamming the windows closed. Otherwise its just a constant pitch.

Before, it would occasionaly go away by restarting the car, but lately that hasn't worked.

Any ideas?

 

I have the same sound on mine (02 S60 T5) and found out it was the ECU cooling fan located on the bottom backside of the ECU box.