Had my serpentine belt and belt tensioner replaced in October of 2005; just prior-to Minnesota Winter Storage.

Now, in July of 2008 [and only 11,000 miles later], the tensioner does not seem to hold proper tension on the belt and the belt has a crack in-it, thus, both requiring replacement [again]...

...what-the-heck would cause such an exagerated "wear" on these items in such a short period of time / mileage???

I am now officially a Parts Runner...

...spoke-with the mechanic late yesterday afternoon ...needed the new tensioner. He said he could have-it by NOON today ...I want to hit-the-road by 1300. So, I told-him I would go and pick-up the part and deliver-it by 0830 this A.M. He thought that was such a good idea that he asked if I could pick-up a few other parts for him while I was there ..."no problem!"

Anything to get the beast back on the road!

I don't know about Cummins engines, but my GM 6.5L TD has a damper pulley on the crankshaft, that drives the accessories. I replaced it because the old one's rubber had gone bye-bye. I noticed something was off because the tensioner was "busy".

Also, with the belt off, check all the accessories for free rotation.

I had a new truck that just ate belts. It turned out this engine had shims of different thickness behind each pully.

It was a new truck and not until I ended up at dealership number 4 did the guy working on the truck ask, "Hey where are the shims?".

Maybe this applies to what you are seeing. None the less I suggest following Rusty's plan first.

Besides I have no idea how to check to see if the pullys are all in the same plane.



Good Luck:

Timothy