I was driving to lunch today and suddenly heard a sound like I had a soda can dangling by a string under the front of my rig (you know that just married sound). It went away before I could pull over and so I decided to continue to my destination. I checked under the hood real quick and just as I thought the belt jumped it's grooves on the air conditioner pulley. After closer inspection when I got home I found that a ribbon of the belt had seperated from the rest of the belt causing the noise. I even found a peice still under the hood.
After doing a short search here the only information I could find were problems with squeaking. Since I've got some noise coming from my power stearing pump I thought they might be related.
Could it be alignment of 1 or more of the pulleys or the tensioner not tight enough or too tight? If so how can they be adjusted? Are the belts directional?

It's a serpentine belt on a 302

 

That would probably depend on alot of things.. helps if you put Truck info in post, what year, how old is the belt, how many miles, color of truck (only for curious minds, has nothing to do with belt )...etc....

 

I think the belt just failed. Buy a new one. When you take the old one off(which is very simple)check all the pullies for slack and make sure they spin freely. Operate tensioner and make sure it's in good shape. If all checks out slip the new belt on and you should be fine.

 

The tensioner is not adjustable, it just works off a fixed internal spring load. My 5.0 tensioner took a 3/8 or 1/2 hex socket or extention to release tension and remove belt. I have seen some belts with directional marks(arrows)on them, just look at the belt before you install it. No arrows or indications of direction, then don't worry about it.