Replace the belt again and do not use any kind of dressing ever on a serpentine belt. It may make it quiet long enough to sell a used vehicle but the dressing collects dust and debris and will make the squealing worse later. Scrub all the pulleys before installing the new belt.
Assuming the spring-loaded tensioner is holding sufficient tension on the belt so it doesn't slip over the pulleys, squealing occurs when the belt walks sideways across a pulley as it goes around it. That is always due to misalignment of one of them. It can be as little as 1/16" of misalignment. Sight down all of the pulleys and look at where the belt rides on each one. If you look straight down, you should only see the belt going over the highest pulleys. You should not see 1/16" of it peeking out to the side, (front or rear of the truck), on any of the lower pulleys. If you do, that pulley or the one right before it is turned or tipped.
Lightly spray a mist of water on the belt just where it comes in contact with a pulley. That will make a squeal due to misalignment show up when you hit the offending pulley.
Thursday, February 28th, 2013 AT 10:28 PM