I hear this sound when I am driving. It sounds like a low whistle or similar type sound almost like air, but not quite. I do not hear it when I am stopped. I also do not always hear it. It is a 2008 Volvo V70 with 60,000 miles.

Any ideas?

 

Does it change when you apply the brakes? Could be related to your brake booster, sounds like it could it be a huge vacuum leak there maybe. Where does it sound like it is coming from?

 

it does change. As I slow down the noise is steady until the car drops below about 30, it suddenly will go away as I stop the car. But as I slow it does seem to taper off with reduction in speed.

 

Is the car turbo?

 

not a turbo.

 

Okay so today i was driving and heard it again, so i decided to roll my windows down. I can not hear it from the driver side, but on the passenger side its a very loud whistle noise. when windows are shut its just a low whirling. any guesses.

 

when windows shut sound is from the front, however windows down its distinctly passenger side/front. I am guessing near the wheel. I suspect a bearing. I have heard crunching when those go, never a whistle though.