My car developed a high pitched squealing noise when slowing down or driving at slow speeds. The noise goes away when I give it gas and speed up. Any ideas what this can be?

 

My 2007 BMW 335i convertible developed a similar squeal under warranty and the dealer replaced the rear brake pads before they were fully worn out indicating that was the cause of the squeal. Afterward the squeal went away; now at 91k miles the squeal is back with still 20+k miles remaining on rear brakes according to iDrive. I will put up with the squeal for a while until replacing brakes and will look into alternate brake pads that may be less prone to squealing.

 

My issue isn't brake related. It sounds like one of the belts are going out. I'm planning to bring the car in for service soon

 

I had the same problem and I found out that it was my belt tensioner so i bought a kit that came with the drive belt and the belt tensioner the bolt and a pulley for i believe for $151.00 on ebay. I replaced them myselft it was fairly easy and the best part is the squeeling whent away..

 

It could be a number of things. The belt tensioner, the belt itself or the pullies. If you have never replaced these since ownership, I would replace them all. You will need to them eventually anyway.