NEED HELP Serpetine belt issues

[tyler]

Hey guys,

So it's been awhile. I have a issue with my serpetine belt or something. My belt is screaming and you can bet when I'm accelerating it's screaming even louder! I changed the belt and the noise went away for three days and then came back. I then changed the idler pulley underneath the alternator and still didn't change anything. The screeching and screaming is still there. Could it be a bad belt that I bought? Should I change the belt again and see if it works?! Could it be the tensioner is loose and I need a new one? When I spray pb blaster on the belt the noise goes away for a little. When I start my TB up right after I spray pb blaster you can hear it as soon as I start for a split second like when the car jumps a little it makes the noise for a split second because I think the tensioner is moving because it's loose. Then after five minutes the PB blaster wears off and belt is still screaming. Not sure what part to throw at it or what to fix? Any ideas anyone?

Thanks!

 

[xavierny25]

I'd never spray pb blaster on belts that's definitely not what it made for. Remove the belt and inspect all moving parts for any odd wobble or resistance. Could well be another pulley. what belt did you purchase?

 

[christo829]

Start with taking the belt off and hand spinning the pulleys. Do any of them feel abnormally stiff or rough? Also, you mention changing the idler pulley, but what about the one on the tensioner assembly? On my old S10, that one wore out and started to wobble before it started to squeal.
Does your belt look glazed? That would tend to indicate a binding pulley, as the belt would glaze as it gets dragged across the stiff pulley.

And, as xavierny25 just pointed out, spraying PB blaster on the belt is not really what it's for. If you lubricate the belt itself, it just slides better across all the pulleys, which isn't what it's supposed to do.

Hopefully it's just the tensioner pulley. That's an easy fix.

Good Luck!

Chris

 

[mrwitty_1]

Very informative video from one one the largest belt manufacturers.

 

[Chickenhawk]

Maybe double-check the belt size. There are two belt sizes and are often mixed up at parts counters. The easy way to remember is that the LONG (915) belt fits the SHORT wheelbase trucks. The SHORT (905) belt fits the LONG 7-passenger trucks.

 

[Sparky]

Check the tensioner arm itelf also. If it gets weak it might not be holding tension properly. Or sometimes the pivot can wear and lean outward, causing belt misalignment. I had that happen on an old car once.

 

[tyler]

Thanks guys I'm going to take this advice and look into it!

 

[Greg Christmas]

When I got my 02 long wheel base two years ago it has a new belt the previous owner had installed due to the screeching noise. It would still scream some. I replaced both the tensioner & idler and (left the new belt) and that fixed the problem. A couple weeks ago the scream returned so I bought a new Continental 4060905. Turns out the old belt was the wrong size (long). The shorter belt was a PITA to get installed but the thing is quiet as a mouse now. The other thing I noticed is there is a rough spot on the alternator, which is probably what started the screaming to begin with, so spin your alternator with the belt off to make sure it's not the real problem that will leave you stranded in a couple weeks.

 

[Mathoran]

Ive had to replace 2 working alternators already due to this problem. Usually it would make noise after it had rained and spraying some wd-40 on the front of the alternator pulley would make it go away for a few days. Kinda have to spin the alternator pretty fast by hand with the belt off to hear it.

 

[KEEBZ489]

check to see if the noise goes away / lessens when you turn on the a/c... I have a new belt , 2 new alternators ( one was no good within a week ), after a few weeks installing the 2nd one there was a screech. I thought the alt pulley at first but using a 18" socket as a stethoscope I couldn't hear it loud enough , I guess idler pulley , replaced it , still there. took a bit of research but the compressor pully bearings go bad and that was the problem. the noise will go away when the clutch is engaged for some reason. I bought a shorter belt to bypass it until warmer weather , don't need the compressor seizing and having a $1000 repair I will pull the pulley to measure the bearing since there seem to be 3 different sizes.