Subject: 2000 Chevy Blazer, 4.3L, 4WD, A/C, 4 Door

I have a extreme squeak coming from a pulley. I have used a stethoscope and was unsuccessful in determining which pulley or where (obviously!). I have replaced the idler pulley, tensioner and pulley, alternator, and the harmonic balancer (all of which needed it minus the alternator. Upon trying to repack the bearings the plastic housing which hold brushes broke, so I got fed up with it and replaced it.) There is no sign of antifreeze weeping out of weep hole on waterpump. It doesn't over hear. A/C works well. I cleaned all the pulleys (twice) with water and dish washing detergent. Tried belt dressing: worked for a day, but caused the tensioner to jump. When it dried and wore off, the tensioner went back to normal. I also have changed the belt a couple of times and cleaned the old one and tried it. Still squeaks. Clutch fan turns as it should by hand.

It usually get louder when A/C clutch kicks on. However once it is driven for 20-30 miles and gets to operating temp it usually appears to stop, but if you really listen it can still be heard. The noise changes as you accelerate. It gets louder until around 55-60mph, but it may still be just as loud but wind, road, and other noises as well as the minor loss due to your speed (i.e. leaving the noise behind) prevent it from being as noticeable.

Any help will be greatly appreciated.

 

sounds like your ac pulley is causeing that annoying squeek

 

The fact that it gets louder when the A/C is on means that it is load dependent. It doesn't automatically point at a bad A/C clutch or pulley bearing though.

Remove the belt and rotate each pulley by hand checking for any play and smooth rotation of the pulley.

 

Sorry. Forgot to mention that I had already rotated each pulley by hand (minus the driveshaft ) All seem to be OK. Hypothetically, if it were the A/C clutch it can be replaced, but can the bearings be repacked?

 

The a/c compressor pulley is supported by a sealed bearing. You have to remove the outer part of the clutch, then a snap ring, and then the pulley & bearing can be removed.

 

Dont put that off. My brother had bearing seize up on him last year. He said the belt had been squeaking a couple days but he didnt think much of it. When that bearing goes, you aint going anywhere. And likely will have to replace the compressor on a perfectly good AC system.

That's just anecdotal hearsay of course, but .. umm.. do you have AAA or does your insurance cover towing?

 

Bearings can go bad long before they lock up. Replacing the bearing before it seizes is a definite good practice so I'm not sure why you would say not to do it... Of course it needs to be confirmed as the source of the problem first, but still... The bearing can be replaced without pulling the compressor from the truck. It's actually quite easy as anyone who has done it would know.

Not sure where you are comin' from 'fog...

 

The worst thing you can use is belt dressing.It's like glue and it doesn't come off easy.What brand of belts did you use?

I had a customer do that to there vehicle and it made it worse.We had to clean all the pulleys with brake clean and then sand down the pulleys and also each groove in the pulleys.Then we used a gator belt and it worked fine.

 

????
You described the process of removing the pulley bearing assy.
I said 'dont put that off' then I described what happened to my bro when he had similar symptoms and ignored the squeaking. And then I described the add'l expenses incurred.
Towing
New compressor and AC system service
Soo.....

Not to mention a lot of times it's lots easier to ID a bad bearing when it's off. You can stick your fingers in the ID, rotate, and if there is any roughness at all it's bad. Otherwise it's a matter of subjective 'amount of bearing sing'
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belt dressing: Should be on a 'must read and check these off' list of no-no's in order to post on here.

V Belt and serpentine are way different. V Belts 'wear out' more than 'age'.
Serpentines 'age' more than wear in normal application.

 

Ah sorry, I misread 'put' for 'pull'. My bad. Long day already. I concur with your statement.