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Squeaky Drive Belt

I drive a 96 Yukon and recently replaced the drive belt as well as the alternator. However, my belt is squealing even worse than it did before. It doesn’t seem coming from my air conditioner–what else could it be? My belt system has a self adjusting pulley built into to it, could this be it?

Your belt is likely slipping. Does it only happen when the A/C is on? Are you sure you have the correct belt installed?

If you have a stethoscope you may be able to listen to where the noise is coming from. If not, or you can’t distinguish…

Take off the belt and by hand spin, feel and listen to each pulley individually. The alternator, the tensioner pulley, water pump etc. You may be able to tell if one or more of these items is squeeking or has excess play in the shaft. The water pump, powersteering and altenator should all spin easily. If they spin with difficulty they may be faulty putting excess load on the belt.

If not, buy some belt dressing and spray it on the belt as it runs. This will help prevent belt slipage. If the noise goes away, it was the belt slipping. Your tensioner may not be holding the correct tension and it should be inspected and replaced as required.

Good luck.

I don’t know if it’s a GM thing but when I put a new Dayco brand (Poly-V/) belt on my 2000 Blazer, it made more noise than the belt it replaced. I took it off and put on a Goodyear Poly-V belt and it was fine.

Ed B.

The squeaking persists with the A/C on and off–so I do not think it is coming from there. Thanks for the advice–I will check all the pulleys and go from there.

That is a legitimate concern, but I put on a belt from a GM dealer, so I would hope that a GM specific product wouldn’t do that…I will look into this–thank you!

[b]It’s becoming normal practice to replace the belt tensioner on a high mileage vehicle when the serpentine belt is replaced. Why? Well, you just found out.


Check to see if all the driven equipment is square with the belt. Sometimes alternators and compressors are mounted on rubber bushings that eventually get pulled out of shape so the component is no longer sitting square as it should.

definitely check the alignment of all the pulleys. If one of them is just a hair off you will get a lot of belt noise. You should be able to see this with your naked eye. Pull off the belt and sight down at least three of the pulleys. You’ll know if all the grooves are lined up or not. I’d suspect the alternator since you just had it replaced. May need to be shimmed in or out.