My Blazer started squealing about a week ago, and it has constantly gotten worse over the week. It is high pitched and seems to be coming from the front right wheel. It makes noise when the vehicle is in motion but not when it is stopped or when pressure is applied to the brakes. I tried replacing the wheel bearings today, but the squealing is still there and does not appear to have changed. Any thoughts?

 

How did the brakes/rotors look when you did the wheel bearings?

My chevelle once started making a horrible racket every time the brakes were pressed. My dad and I tried everything, and couldn't get it. Weeks later I had to get the transmission repaired, and while it was on the lift, I noticed a smooth, clean area on the drive shaft. Turns out the exhaust had sagged just enough, so that it rubbed the shaft. The weight transfer from breaking changed the driveshaft angle just enough to contact the exhaust. Stready speed, and acceleration, it cleared it.

Moral is, it might be something totally unrelated to what you think. check everything that moves while the car is moving.

 

^^^Don't know what year Blazer you have (or if it matters), but all my Blazers have had "squealers" on the brake pads to let you know it's time to change them. Pretty embarrassing sound and irritating as hell, which is probably the point. It's just a bent piece of metal on each pad that contacts the rotor when your pads are super thin and it's warning you to do the brakes before your rotor gets ate up by the rivets in the brake pads.

 

Is it possible that its just an old belt? or worn out idler or tensioner pulley
Edit: spray silicone on the main belt to see if it stops