Mechanics

SERPENTINE BELT KEEPS JUMPING.

1997 Pontiac Sunfire • 4 cylinder FWD Automatic • 228,000 miles

I have a 1997 Sunfire 2.2 that the A/C compressor siezed on. So rather than go to the expense of servicing the ac I bought an Dorman A/C compressor bypass pulley. Here's the problem I run into: The ac compressor bypass pulley has 5 "ribs" the alternator has 4 the ps pump has 4 and the crankshaft pulley has 5 I believe. So if I align the belt to the left the belt wants to fly off the ps pump and the tensioner. If I align the belt on the right side of the ac bypass pulley the belt rides normally on all pulleys and does not rub against the engine, except the crankshaft pulley. It rides on the inside edge of the pulley (closest to the engine) and I though ok at least it's not flying off so I'll drive it this way and maybe it will work itself into it's own grooves and it seemed to be doing that slowly. Problem is now the belt is splitting on that inside edge from the way it's riding the crankshaft pulley. I am at a loss. What is going wrong? It seems that a fraction of an inch either way, wreaks havoc. I should also mention that I have also bought and installed a new tensioner.
Thank you for any help.
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Billd75
March 5, 2011.




Sounds like the dorman part is slightly out of alignment?(China) maybe a shim(s) would help? And even if belt is splitting as long as it's still working minus that edge rib your ok? At least temporarily?

Tiny
Fixitmr
Mar 5, 2011.
Thank you for your prompt reply! Great answer too, lol. Yes that does seem to be the problem as, today I checked it out and the bypass pulley does stick out further than the crankshaft pulley, so I have removed the bypass wheel and bracket and I am going to put a washer or two behind the bypass wheel to make it stick out a bit more and line up with the crankshaft pulley properly. I guess switching grooves works as a temporary fix but does not actually solve the problem. I did drive the car to pick up a new belt and the old one shredded on the way home, but at least now I have a better solution to permanantly solve the problem. Thank you again for your help, it just took me eyeballing the pulleys again as you suggested to find out that the ac pulley IS the culprit here and I think I got this problem beat now.
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Tiny
Billd75
Mar 5, 2011.

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