AC Belt throwing / routing help
Thread Starter
Joined: Aug 2006
Posts: 366
Likes: 83
From: Tuscaloosa, Al
AC Belt throwing / routing help I thought I would post this info that might help someone in the future, I recently had some issues throwing A/C drive belts only at high rpm (I shift at 6500 just for reference), I could cruise around all day fine but a couple of high rpm sprints would throw it every time. Installed a new tensioner and still had issues, checked alignment, balancer etc. everything seemed fine then I looked a little closer and found that my A/C belt rides right on the front of the idler/tensioner pulleys, over time it had chipped away a couple of little spots no more than 1mm wide on both the old plastic tensioner pulley and the idler pulley. I think just those little gaps in the front of the pulleys + just the right amount of speed/harmonics were just enough to throw the belt so I did some research and found that Gates part# 36220 is a steel pulley that fits both A/C idler & tensioner and it is 3mm wider than the original equipment & any other aftermarket pulley I could find (23mm vs 20mm) this effectively on gave me 1.5mm more to the front but in this case that's all I needed and I didn't have to mess with spacers or anything else that would effect bearing life, this along with a fresh tensioner seems to have fixed my problem, I will try to post pics up later but wanted to go ahead and post this just in case it can help someone who is having a similar issue.
Thread Starter
Joined: Aug 2006
Posts: 366
Likes: 83
From: Tuscaloosa, Al
Shredded 2 gates belts + the belt that was already on it, has a advanced auto brand on it now, says made in America on the belt, was never a belt issue and took 19 years to chip away at those plastic pulleys enough where it would jump them. No difference between A/C on or off.
Last edited by speedfreak440; Jul 8, 2020 at 09:31 AM. Reason: Forgot 1 piece of information
Thanks for posting. For years, the Dayco 89135 Pulley has been most people's go-to part for this pulley replacement: http://www.daycoproducts.com/part?pa...number%3D89135
It's also metal. I can imagine the original plastic pulley will get more brittle over time (and chip) but am also amazed that your bearing lasted this long on the original part. Many of us have had to replace these pulleys long ago due to squealing.
It's also metal. I can imagine the original plastic pulley will get more brittle over time (and chip) but am also amazed that your bearing lasted this long on the original part. Many of us have had to replace these pulleys long ago due to squealing.
Thread Starter
Joined: Aug 2006
Posts: 366
Likes: 83
From: Tuscaloosa, Al
It helps that the car only has 54k miles on it, but 19 years is still a long time, I think time & heat cycles are what got the plastic, having that little bit of extra pulley width makes me feel a little better too because it's not running so close to the edge, probably didn't matter much since it rode that way for dang near 20 years but still 
