Hi,
I've got a '97 6cyl EL Fairmont. The serpentine belt (all in one drive belt) is wearing really quickly from the outside/closest to front bumper edge, and on the smooth side of the belt.
I replaced it because it completely shredded, have done about 50Kms to drive it home, and the new one is already very worn, so much that I don't think it will get another 50km even. It looks like a pulley might have come off the water pump, because there is only a short grooved rod coming out that runs along the underside (smooth side) of the belt, and the belt has worn a groove in the water pump. However, I'm not sure if the water pump was like that already or not.
The water pump rod seems to be wearing grooves in the smooth side of the belt also.
What do you think is causing this and how do I fix it?

can you post a pic?
could be the tensioner thats causing the problem..

The water pump should have a black pulley pressed onto the front shaft. I would say you need a new water pump. There should be a sticker on the underside of your bonnet with a belt diagram...

Check the alignment of all the pulleys, as a faulty harmonic balancer is a common cause of belt failure.