Gentlemen,
As long as I've owned my 2004 F150 XLT 5.4 4x4 I've always had issues with an annoying squeal from the belt. This past Summer I had a belt snap on me while I was driving, I replaced it and the right upper Idler pulley which had a slight wobble, and all was good.....for a little while. Eventually the squeal returned.
Now about a month ago, while changing the oil, I notice the right Idler pulley caked in belt rubber and the belt badly unevenly warn on the smooth side.
I change the belt and the second Idler pulley and all is good again. I drove a little over 1000 miles and the squeal returned. I checked under the hood, and to my horror I observe the new smooth pulley again caked in rubber and the new belt unevenly warn on the smooth side.(Please see photos)
Now I ask:
Have any of you had this problem?
What was the cause?
What was the solution?
Thank You In advance for your responses......Joe


What you're looking at is the smooth pulley and the smooth side of the belt.

 

If you have grooves on the smooth side of the belt then maybe it's routed wrong. The pulleys with the grooves should not contact the smooth side of the belt.

 

That would definitely seem like the logical explanation, but I don't believe it to be the case.

 

Not arguing but I wonder what's making the marks on the smooth side of the belt?

 

Looks like he "flipped" the belt when it was put on. The alternator pulley wheel is grooved but yet the grooved side of the belt doesnt run in the grooves.
The squeal he is hearing is the belt slipping because it's installed flat side to grooves. That's my guess.

 

But just in case its not ,I had an alignment problem on one engine . The crank pulley was out of line with other pulleys .I had to tighten the crank pulley until it lined up up . After that no more broken belts . You would have to do this very carefully and have a good eye .

 

Yeah, it looks like the belt grooves are in contact with the smooth idler

 

This for sure would be my first guess ...Belt seriously looks inside out...got any pics of the other side of the belt...
Either that or you have another pully that is stuffed....that you can't see and its wearing all the rubber off the smooth side?

 

I would replace the tensioner.
Also, a gatorback is a good belt for your money. Not a sound out of it for me. Even the wot squeal, that my old belt would make.

 

Remember there isn't a one of us that hasn't made a dumb mistake .That's how we learn . You just have to laugh at yourself as long as it's not a too costly a mistake .. I tell lots of oops on myself .