Hey guys, I have a 91 F-150 with a 5.0 in it and for the life of me I can figure out which pulley is squeaking. The first thing I did was replace the belt and idler pulley, and the alternator is also fairly new. But I can't seen to figure out which pulley is making all the noise, and I don't want to keep dumping money in with no results. Anybody have any idea what I should try next?

 

Welcome to the site.

Constant squeal or rythmic squeak? Is it the belt or something mechanincal?

Depending on the belt, I've had the waterpump pulley give me fits. The lettering on the belt would chirp as it ran across it. I've also taken some sandpaper and roughed up the waterpump pulley to give it some traction.

Is the tensioner spring weak? How hard is it to move to get belt off?

 

It is a constant squeak, the belt tensioner is strong it's pretty hard to get the belt off. I'm almost certain it is a pulley.

 

Remove the belt and see how easy the air pump spins? It might be near locked up and causing the squeak. Only other things are water pump and power steering. The a/c should spin easy when not engaged. I've seen the bearing the a/c clutch go bad and make noise. Might want to just spin it and see if it makes noise.