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73-87 Chevy _ GMC Trucks => 73-87 Chevy & GMC Trucks => Topic started by: Unofficial on August 14, 2009, 01:25:09 am

Title: HORRIBLE squealing under hood.
Post by: Unofficial on August 14, 2009, 01:25:09 am
Last winter and even in the spring and fall, when it's cooler out, my truck will squeal like crazy when I start it up. It's odd because sometimes when I try and start it, the starter will turn over for a couple turns and just run on... It won't fire up. I give it gas while starting and it fires up but there is a terrible squealing under the hood. It's WAY too loud for a belt squeal, and it gets louder with RPMs. It must be putting a drag on the engine too, because it will stall quite often. For the stalling, I got a new IAC valve, and it runs better, but still stalls when slowing down and putting into drive/reverse. I can't think of anything else. I've replace the alternator, power steering, and the p/s belt. Can anyone think of anything else that will squeal like this?

By the way, it's a 350 TBI
Title: Re: HORRIBLE squealing under hood.
Post by: Prong on August 14, 2009, 05:49:26 am
Checked the water pump bearings? They can do that.
Title: Re: HORRIBLE squealing under hood.
Post by: zieg85 on August 14, 2009, 08:53:04 am
You would be surprised how loud a loose PS belt is, but I am sure you have checked that already.
Title: Re: HORRIBLE squealing under hood.
Post by: DnStClr on August 14, 2009, 09:07:12 am
Well that's kinda weird that it only squeals during cool weather. I was gong to suggest a bad a/c compressor clutch.
Title: Re: HORRIBLE squealing under hood.
Post by: Lt.Del on August 14, 2009, 10:16:51 am
any bearings will put a load on the engine, even the alternator bearings.  I had to rescue a buddy of mine while he and his wife drove down the interstate.  The engine just seized up.  They coudln't figure out why.  They tried starting it but the battery wasn't powerful enough.
Turned out to be the alternator had seized.  That, in turn, seized anything associated with the belt--since the belt couldn't move. 

I say take your belt (s) off the part (water pump, alt, power steering, a/c) one at a time and turn the pulley of that part with your hand and see if you can find out anything. See if it wobbles, or if it doesnt turn smoothly, whatever. 
Title: Re: HORRIBLE squealing under hood.
Post by: Unofficial on August 14, 2009, 10:21:52 am
My alt. pulley was squeaking when I turned it with the belt off, so I replaced the alternator. I also replaced my power steering pump and belt. Won't my water pump leak or something before going out?

Also, is there any way it could be my harmonic balancer? I'm pretty sure the rubber ring is bad and the outer part slipped. The reason being is because when I tried to time it, I put the mark on TDC and it wouldn't even run...
Title: Re: HORRIBLE squealing under hood.
Post by: Donut on August 14, 2009, 10:36:47 am
Water pump will usually leak before going, I just changed mine because I noticed a shaft wobble before any leaking started.  If the balancer ring has slipped, it wouldn't hurt to change that also.  I can just imagine the damage if the outer ring came off.
Title: Re: HORRIBLE squealing under hood.
Post by: DnStClr on August 14, 2009, 11:27:47 am
If you suspect that the balancer rubber ring is bad you should get a new one. You know, if you can move the outer ring it's not good. You getting vibration while the engine is running?
Title: Re: HORRIBLE squealing under hood.
Post by: jimbo on August 14, 2009, 12:12:48 pm
Sounds like you have been replacing things without truly finding the culprit first.  I would take all the belts off and crank it. Then start from there if it does not squeal.  Install one belt at a time, check all pulleys, etc.
Title: Re: HORRIBLE squealing under hood.
Post by: DnStClr on August 14, 2009, 08:59:51 pm
I agree. That's the way you should go.
BTW if you get to the end and the squeal is still there, don't forget to check the distributor for a rusty bearing.   
Title: Re: HORRIBLE squealing under hood.
Post by: joesgarage71 on August 14, 2009, 10:49:18 pm
I agree. That's the way you should go.
BTW if you get to the end and the squeal is still there, don't forget to check the distributor for a rusty bearing.   

Don, distributors have bushings
 TBI huh, loud squealing, makes me think it has a bad belt tensioner
Title: Re: HORRIBLE squealing under hood.
Post by: Irish_Alley on August 15, 2009, 05:52:06 am
TBI huh, loud squealing, makes me think it has a bad belt tensioner
x2 it would seam to me like the tensioner is OK till it has to work against thick power steering fluid causing it to squeal. buy a stethascope from autozone or advance and put it on the bolt that goes to the belt tensioner pulley the go to the alt then water pump then powersteering pump and see where the noise is louder. or you could use a long screw driver
Title: Re: HORRIBLE squealing under hood.
Post by: DnStClr on August 15, 2009, 07:24:56 pm
Ha. And I just replaced mine! thanks for correcting, Steve.. :-[
Title: Re: HORRIBLE squealing under hood.
Post by: eventhorizon66 on August 15, 2009, 08:40:11 pm
I thought '87s still had V-belts.
Title: Re: HORRIBLE squealing under hood.
Post by: gold84gmc on August 15, 2009, 09:03:05 pm
mine isnt a LOUD squeal but when its damp or wet outside and my truck is idling the belt(s) (i think is whats making the noise) squeal a little bit...but they only do it when its wet out and when its idling
Title: Re: HORRIBLE squealing under hood.
Post by: Unofficial on August 15, 2009, 10:51:03 pm
Sounds like you have been replacing things without truly finding the culprit first.  I would take all the belts off and crank it. Then start from there if it does not squeal.  Install one belt at a time, check all pulleys, etc.

Actually, I DID check everything. I took the p/s belt off, still squealed. I put the p/s belt back on and took the alternator belt off. No squeal. I double checked to make sure, and then I spun the alternator pulley and it squeaked as it spun. So I replaced it. I replaced the p/s pump because it's been bad for a while now, I just got around to replacing it, which eliminates that from the possibilities.

Also, I don't have A/C, nor a tensioner pulley. And yes, I have a v-belt for the p/s pump and a serpentine belt for the alternator.

It's funny because the alternator belt looked fine, which is why I didn't replace it, but I figured I might as well... So I picked up a gator-back at the zone and it's fine now. I don't really mind though because my alternator was obviously bad if it was squeaking when the pulley was spun, and like I said, my p/s pump was already bad in the first place. So I don't even feel stupid, because now my accessories and new and everything's working fine.  :)
Title: Re: HORRIBLE squealing under hood.
Post by: Lt.Del on August 15, 2009, 11:18:48 pm
Glad you got it figured out. 

[Bowing-as I hope you read my thread of the 14th.]

Ok, lucky shot. 
Title: Re: HORRIBLE squealing under hood.
Post by: DnStClr on August 19, 2009, 01:43:29 pm
 :D
Actually zieg was pretty close just before you stumbled across it .
Title: Re: HORRIBLE squealing under hood.
Post by: Marc on August 19, 2009, 02:34:56 pm
sometimes what I have seen happen is the sides of the little grooves in the belt will wear so much that they will bottom out on the pullies.  Since there is so little area there for it to transmit power it will slip and squeal.