94 chevy 1500 belt drive issue

[BigbadBill4x4]

Hello there.I have a 94 1500 4x4 with a 5.7l.I have been having issues with what I think is my belt drive.Occasionally when I start it after it has been sitting a day or so,my serpentine belt will squeal and move around on the idler quite a bit.It has actually came off the idler a time or two while doing this.Well,now it has been making this rattling/clattering noise while also making the squealing noise.Yesterday was the worst it had done it yet.Before it would just rattle and the go away,this last time it sounded as if something was going to fly apart.I shut the truck down and restarted it,noise still there.Shut down and restarted a 3rd time no noise,everything running fine.I restarted multiple times with no issues.Today,I went out and started the truck,nothing,running like it should be,no issues.One thing I have noticed is I am getting build up of rubber on a new tensioner pulley from a new belt.The belt I had on while it was doing all this crap was an old belt that I had kept,I put it back on there because it was the new belt that I had initially been having trouble with walking off the idler to begin with.I know this is a long post,but I am completely stumped by this and wanted to give as detailed a descrition as I could.Thanks in advance.

[j cAT]

Originally Posted by BigbadBill4x4

Hello there.I have a 94 1500 4x4 with a 5.7l.I have been having issues with what I think is my belt drive.Occasionally when I start it after it has been sitting a day or so,my serpentine belt will squeal and move around on the idler quite a bit.It has actually came off the idler a time or two while doing this.Well,now it has been making this rattling/clattering noise while also making the squealing noise.Yesterday was the worst it had done it yet.Before it would just rattle and the go away,this last time it sounded as if something was going to fly apart.I shut the truck down and restarted it,noise still there.Shut down and restarted a 3rd time no noise,everything running fine.I restarted multiple times with no issues.Today,I went out and started the truck,nothing,running like it should be,no issues.One thing I have noticed is I am getting build up of rubber on a new tensioner pulley from a new belt.The belt I had on while it was doing all this crap was an old belt that I had kept,I put it back on there because it was the new belt that I had initially been having trouble with walking off the idler to begin with.I know this is a long post,but I am completely stumped by this and wanted to give as detailed a descrition as I could.Thanks in advance.

I have issues with auto part stores and belts...they do not for some reason have the correct belt listed for some of our vehicles..this is why I never throw away the oem original belt..this I use as a reference ...

the width and length are important it must be correct..

next is the idler/pulley/bearings and spring tensioner must be good..with belt removed make sure they are rotating smoothly and the spring tensioner is not worn../rusted binding etc......

other items like the ac compressor pulley can seize up ...

[brcidd]

Three times in my life, I have seen C/K trucks of your vintage have the belt wrapped wrong- and do what you are describing--are you sure you have the belt going from alternator down to power steering pump, then to water pump pulley, then crankshaft drive pulley? I have seen them routed from alternator back to water pump which is wrong...causes loose belt and squealing and flopping tensioner-- although it will run ,

In another scenario, I have seen the belt be flung off the idler (not tensioner) pulley when a/c is turned on- due to liquid refrigerant slugging within the a/c compressor-- I actually have this video taped in slow motion- on '93 - 94 trucks. if the belt goes inward-- goodbye belt and a/c compressor wiring harness-- if belt flops outward- then it merely drops in beneath the idler- and causes another loose belt scenario- but truck still runs fine otherwise. Just tensioer arrow is outside the window.

You can also check your tensioner for proper position- is the arrow within the two marks on the base- look at it closely- you'll see the window and alignment arrow-- I've seen wrong belts throw that arrow way off to one end.....

[BigbadBill4x4]

Hey Jcat,thanks for the reply.When I first bought this truck the belt was squealing like a SOB.I finally got tired of it and went to the parts house and bought a new one.He gave me a belt based on my description of my truck,has a/c,does not have a smog pump.So,when I got back home,before putting it on I compared part number from new belt and the offending noise maker on my truck,realizing they are the same part number.I took an old belt that was still with the truck into him and he crossed the number and said it goes to an engine with a smog pump which mine does not have.So,I decided to take that belt since it is slightly longer and the other belt was in my opinion way too tight,hence the squeaking.Back to the original point.I have had the belt off numerous times and have checked all the pulleys and they seem to be fine.Here awhile back,I started hearing a slight hammering noise on cold start.The noise never really got very loud but did give me cause for concern.I determined that it was not internal but somewhere in the belt drive because I could give it a shot of wd-40 and it would go away.It would go away instaneously if I sprayed the a/c comp.pulley.A friend of mine came and brought a mechanics stethoscope and we tried to track it down,listening to all pulleys,we could not pinpoint an exact location.I blamed the a/c pulley since if I sprayed it,noise would immediatly go away.I decided to live with it until this new issue.Thanks for the help.

[BigbadBill4x4]

Yes,the belt is routed correctly.Sorry guys if my replies posted multiple times,my browser was being a turd and I didn;t think my reply was uploading.I was wrong,sorry.

[BigbadBill4x4]

Also,I don't believe the a/c comp.is to blame since it is non-operational and void of freon.So,it is basically just a pulley.

[j cAT]

Originally Posted by BigbadBill4x4

Also,I don't believe the a/c comp.is to blame since it is non-operational and void of freon.So,it is basically just a pulley.

that is not correct.........the ac cmpressor pulley bearing has nothing to do with the compressor working or not refrigerent or not..

this is simply a bearing that the pulley rotates/supports..if that bearing and I have seen a few gets seized, this will do as you have issues now...soon it will lock up...then your not going anywhere..

this is almost 100% on the lumina/monte carlo's of the 90's seen many.

[BigbadBill4x4]

I get what you are saying and that is exactly what I am saying.Without the compressor functioning,I don't beleive the noise is coming from inside the compressor.I have considered it being the pulley itself and am keeping an eye on it.Since the noise is short-lived it is hard to pinpoint it as an exact source.It makes sense that the pulley would be on its way out since it is the next pulley after the idler and if it is binding or whatever,that would cause the jumping around on the idler.My concern is the noise that it has started making.I mean,this thing makes a racket like something is gonna fly apart.Since the compressor is not charged and working,I have jumped the connector to the low pressure switch and got the compressor working and it functioned very well,no noises at all.My opinion is that if the bearing is failing,the extra load from the clutch engaging and engaging the compressor,the sounds would be more evident.Just a thought,I am not a mechanic by any means,but I try to think logically and don't want to just throw parts at something in hopes of nailing the issue.Thanks again,sir.

[j cAT]

Originally Posted by BigbadBill4x4

I get what you are saying and that is exactly what I am saying.Without the compressor functioning,I don't beleive the noise is coming from inside the compressor.I have considered it being the pulley itself and am keeping an eye on it.Since the noise is short-lived it is hard to pinpoint it as an exact source.It makes sense that the pulley would be on its way out since it is the next pulley after the idler and if it is binding or whatever,that would cause the jumping around on the idler.My concern is the noise that it has started making.I mean,this thing makes a racket like something is gonna fly apart.Since the compressor is not charged and working,I have jumped the connector to the low pressure switch and got the compressor working and it functioned very well,no noises at all.My opinion is that if the bearing is failing,the extra load from the clutch engaging and engaging the compressor,the sounds would be more evident.Just a thought,I am not a mechanic by any means,but I try to think logically and don't want to just throw parts at something in hopes of nailing the issue.Thanks again,sir.

since you do not use the ac ...I would start looking for a ac compressor bypass pulley...rather than install another compressor....

not sure on your setup if you can use a different belt to bypass your compressor /but if so do it......

removal of the belt when cold then check all pulleys..you should feel which one is bad...

[BigbadBill4x4]

Thanks for all your advise J Cat.I plan on using the a/c,I just need to replace the lines first.If it indeed is a bad comp pulley,I will replace it.The thing that I am hung up on is the fact that I have had the belts off and have spun all the pulleys and they all feel and sound good.Like I said before,a friend brought a stethoscope and we listened to them all and even then one didn't stand out more than the other.Ever since I started this thread,I put the belt back on that I had bought to replace the sqeaking belt and have cold started it and even drove it to the store and have not had an issue.The only reason I took that replacement belt off and put the older,cracked up,slightly dried out belt back on is because the replacement was for some reason riding close to the outside edge of the idler and occasionally walking off.Perhaps the old belt is a source of the problem,I don't know.I will keep tabs on it and see if does it again with this other belt.