I bought this vehicle about 2 mos ago, we like the vehicle but this problem is driving us crazy. Below are the things that we've tried, to quiet the serpentine belt squealing:

1) Sprayed belt conditioner on it, made it louder
2) Sprayed WD40 on the belt, worked for a few minutes.
3) Changed the AC Pulley/Clutch
4) Changed the belt tensioner
5) Changed the idler pulley
6) Changed the waterpump.
7) Changed the fan clutch
8) Changed the alternator
8) Cleaned all the pulleys with wirebrush, brake cleaner and compressed air, then installed a new serpentine belt.

This seemed to work for about an hours worth of driving. Now it squeals sporadically, when first run for about 10 minutes, then the squealing goes away and re-occurs. The only other pulley we haven't changed is the power steering pump.

I'm thinking that maybe one or more pulleys are not lined up properly and the misalignment causes it?

Any help would be appreciated, thanks.

 

What brand of belt have you been using? I have had the squeaking problem on these trucks (including fullsize trucks) with Dayco, Gates, and other well known, premium belt manufacturers that went away once I installed a Goodyear Gatorback belt.

 

Okay, we had a Gates originally and now have Dayco. I will try the Goodyear Gatorback next, thanks a lot for the quick reply!