2002 yukon xl 5.3l Serpentine Belt Tensioner Pulley maxing out

I have a 2002 yukon xl. One day out of nowhere the Serpentine Belt Tensioner Pulley kept maxing out, forcing the serpintine belt to rub on, what appears to be, the transmission fluid lines. This only occurs when the air conditioning is on, and when the rpms go above around 3500 (in other words when pulling out or merging). I tried a replacement pully and a new belt, but this did not correct the problem. The pulley, by the way, was aftermarket, not GM. Any help or ideas will be greatly appreciated.

Thanks

Welcome to AF, is the pulley the same diameter as OE?? If so you may try a belt say 1 inch shorter, although why should you have go away from oe, are you sure the tensioner is working properly? BTW are cooler lines properly routed?

Welcome to AF, is the pulley the same diameter as OE?? If so you may try a belt say 1 inch shorter, although why should you have go away from oe, are you sure the tensioner is working properly? BTW are cooler lines properly routed?

Same diameter. I'm wondering if the GM one is maybe a little stiffer so it won't max out as easily. Maybe the compressor is going bad??? Any thoughts????

Thanks,

G

If the tensioner has to go out to it's extreme, either the belt is routed wrong or too long, assuming all other components are correct.

How many miles on the unit?

Were the parts you purchased name brand quality parts or cheap generic? The US is flooded with cheap imported parts, very many of questionable quality.

I would have the AC compressored checked out, sure seems like something is wrong there.

Sounds like the AC is shot. Had the same problem on my 2002. Replaced all of the tensioners. When the AC was on it would make a ratcheting noise due to the inside of the AC compressor being junk