A couple of days ago I was looking over the engine and noticed that my serpentine belt was chewed up on the side facing the engine. As I was replacing it, I actually pulled out an 8 inch long sliver of belt that had been lodged around the crankshaft pulley. I got the new one on just right and started the truck to test it. It was well aligned on all pulleys but the a/c compressor. It was running basically on the back edge of it. I realigned the belt on that pulley and had my girl start the truck as I watched. As soon as the engine turned over, it jumped backward on the pulley.

I think this is the culprit that is eating my belt, but I didn't see a way to adjust it forward or backward. Is there a way? If not, is there any other way to get this lined back up. I haven't touched anything in that area except for change the alternator out a few months ago. but this seems lined up fine. I appreciate if anyone can shed some light on this for me.

 

I suppose the belt was OK before you changed the alternator? And now you don't think the alternator is at fault? Check it again.
I have heard of the idler bearing going bad and causing belt misalignment. Lots of related threads on the forum. Do a search.

 

It's probably a worn belt tensioner.

 

Funny you say that Timmy. I was just reading a post about a 1st gen that had the identical problem. Turned out it was the tensioner. Maybe when I loaded the tensioner to take the belt off the alternator, it was the last straw. I hear they're cheap so I'll change it next. Thanks for the help guys!

 

I had this happen also.. a few months ago (before i bought the truck) I saw in the maint. file that the alternator was changed. Well the belt was frayed and screwed up.. upon checking i found the pulley on the Alternator was missing a few grooves on it... causing it to fray and destroy itself. I checked the alternator and it was the right one but had the wrong pulley on it. I got the correct pulley from NAPA and have had no problems since.. hope this helps...

 

Also had this problem on my truck... replaced the tensioner, but same thing, turn the engine over and belt raced for the timing cover.... found that the PO hadn't tightened bottom alternator bolt completely - causing the lower 'ear' on alternator to wear into the mount on the engine (actually the water outlet). Bolt was worn, upper bracket was bent. Quite a hassle to find, and certainly hope this isn't your problem, but something to look at.

Fixed with a new alternator, water outlet (a/ comp, lower hose, and alternator mount to this), upper bracket, and bolt. 3K miles and no issues...