So I've been having horrible problems with my S/C belt (basically since the start). Gone through about 4 in 6k miles so far. Currently I have a NAPA 040250 which is 9/16" x 25 3/4" (14mm x 655mm) but it's stretched/torn up from riding up on the edge of the pulley. From what I have heard this is larger than anyone else is using, but my shop claims they can't get anything smaller on there. I watched them check the alignment and the S/C pulley and it is perfectly positioned above the alternator. I imagine what is happening is the belt stretches, and the tension pulley is pushed back as far as it can go... so there's no way to keep it on there snugly once the belt stretches out.

I went to replace it with one of the same size but could only find a Gates belt in the same size locally. Problem I noticed right off the bat though is that although the width and length are identical to the NAPA one, the belt thickness is almost twice what my current belt is. Is this going to be a problem for fitment? It's a Gates K040250 4KP645. I'm going to see if I can find a Gatorback 040252 4KP640 and give it a shot myself... but the shop couldn't get that size on there so not sure I will have any better luck. Getting tired of having to clean my engine bay from black belt particles...

 

If you don't Brandon to order it for you call him and ask where he ordered mine.

 

I had my install done at Comptech and they used the Goodyear, no problems so far ( Knock on wood )