Persistent belt squeal continues

[Finnegan1008]

Based on the advice from another thread, I just went through the exercise of aligning all of my pulleys. Along with this, I replaced my wobbly crank pulley, replaced my harmonic balancer and put all new belts from hillbilly wizard.

This eliminated my best squeal for about a week.

Since then I’ve put about a hundred miles on the truck. At first, the truck was producing a slight squeal on a cold start if I gave it any throttle. This would clear up pretty quickly once the engine came to temperature. Now I noticed the squeal is becoming more persistent, and the Belts now starting to squeal momentarily from a dead stop.

My belt tension seems adequate, I’m resisting the urge to increase the tension and risk of abusing alternator bearings.

I’m wondering if maybe I have an accessory that’s starting to go bad? I have what I think is a slight bearing noise coming from one of my alternators. When I start up my GEN 2 light will stay on, and my electrical gauge will read below 24 V until I blip the throttle then the light will go out in the gauge will go back to 24 V. If I do this the GEN light will stay off.

I saw a YouTube video where a guy change the alternator pulleys out and supposedly eliminated his belt squeal, to me it sounds weird that the factory pulleys wouldn’t work with a fairly standard belt.

Does anyone have any ideas on how to fix this? Could one of my alternators be going bad causing too much resistance?

 

[Barrman]

A few things came to mind while reading your post:

How old are your batteries and are they fully charged? Mine only squeal on start up if they have been sitting a long while, very, very long glow time or if I left the lights on.

Try tightening the belts just a bit more. They stretch out the first few heat cycles they go through. That might end it.

The alternator pulleys are stamped steel. They can widen out over the decades and let the inside surface of the belt touch the pulley. The load is supposed to be carried by both sides of the belt. Look at your pulleys. You can see the little step in there the belt is supposed to be on. If you have the proper belts, they should be higher than the edge of the pulley when tightened up. If the belt and the pulley are even or the pulley rim is above the belt. Your pulleys are spread or you have belts that are too thin.

 

[Finnegan1008]

Batteries have tested healthy, I will try a little more tension I noticed one could probably use it.

Is the GEN2 light staying on at startup normal? It clears with a little throttle, the gauge goes to green and then stays off.

This weekend I want to start cleaning electrical connections in case there is any fowling

Also one of my Pulleys is level with the belt. I know they make solid ones and may swap it

 

[cucvrus]

The Gen 2 staying on at startup is normal. The voltmeter should be in the upper green. there is a little tick mark on the stock voltmeter. The needle should stay there on a properly operating CUCV in stock form. But bypassing the resistors on the firewall will make the Gen 1 squeal hard because you are pulling all the voltage out of the front battery to light the glow plugs. No modifications are needed. The CUCV works fine for all these years in stock form. I drove them 27 years without any fox head rely conversions or cascading glow plugs. Did I have glow plugs and relays fail in 27 years. YES. I replaced the parts that failed and drove on. Good Luck, Be Safe and have a great weekend.

 

[antennaclimber]

You may also want to verify that your glow plugs are not on all the time.

 

[87cr250r]

Did you use the Gates brand belts? They're the only ones that tolerate the CUCV setup.

 

[juanprado]

Might sound crazy but old school:
Use a bar of soap and let the belt rub on it running.
Does sound go away? Belt is suspect old or dry.
Move on to each belt and repeat.

 

[CenterMass762]

Mine does the same thing with the Gen 2 light staying on and low voltage until I blip the throttle. The generator has been needing replaced for a solid 6 months, as evidenced by the very slight glow of the Gen 2 light all the time. It still charges, though, so I haven't got around to replacing it. Maybe your alternator is going bad, too.

I had the same exact belt squeal problem, too. Tightening the belts a bit solved the issue. They were brand new belts so they stretched and loosened a bit while breaking in and started to squeal.

 

[cucvrus]

I have a local alternator shop that fixed that faint glow of Gen 2. I also had him install self-exciting voltage regulators on a CUCV plow truck because I had nothing but trouble with the idiot lights and the people driving it without knowing if it was charging or not. He did something to my truck to eliminate the low glow of Gen 2 a common issue. I think a relay was added or something. Not sure anymore. But it worked great and I have since sold the CUCV's I had as personal drivers.

 

[87cr250r]

It's normal for the light to stay on until you bump the throttle.

 

[CenterMass762]

It's normal for the light to stay on until you bump the throttle.

I believe it even says something to that effect in the TM.

 

[BGR]

Mine does the same. One belt is a little longer then. the other so Im chalking it up to the left and right belts being mixed up. Perhaps that is your issue as well.

 

[cucvrus]

My advice is to go to the parts store and take whatever tools you need to change the belts. Remove the belts and push the alternators all the way into the lowest point in adjustment. Take the Gen 2 belt in and ask for one shorter and take the new belt and slip it on Gen 2. Did it go on easy? If it did go back in and get one a bit shorter. I actually get a belt that fits tight enough that I can use a wrench and spin the pulley of the alternator to get the belt on. Tighten it and move onto Gen 1. I spin the alternator pully with the center nut of the pulley. I did it for years and eliminated belt squeal. I live in a small town and the Men at the parts store know me. It works at Autozone also. I have not found that a particular belt number fits every CUCV. At one time GM OEM belts were Dayco and they were the perfect fix. I even used green lawn mower belts and red Kevlar belts. They worked. I mean a lawn mower takes a lot of abuse. Do as you wish. But once the pullies are polished and shiny, they will rust very quickly and chew belts up fast. I had me pullies changed to solid pullies and tossed the stamped pullies. Good Luck. Stop squealing on each other. No body likes a Squealer.

 

[Finnegan1008]

I’ve got a good fit on my belts all of the accessories are in the middle of the adjustment range. I think my alternator pulleys have been spread out over years of abuse. I plan to change them with solid steel units.

 

[deercoker]

My advice is to go to the parts store and take whatever tools you need to change the belts. Remove the belts and push the alternators all the way into the lowest point in adjustment. Take the Gen 2 belt in and ask for one shorter and take the new belt and slip it on Gen 2. Did it go on easy? If it did go back in and get one a bit shorter. I actually get a belt that fits tight enough that I can use a wrench and spin the pulley of the alternator to get the belt on. Tighten it and move onto Gen 1. I spin the alternator pully with the center nut of the pulley. I did it for years and eliminated belt squeal. I live in a small town and the Men at the parts store know me. It works at Autozone also. I have not found that a particular belt number fits every CUCV. At one time GM OEM belts were Dayco and they were the perfect fix. I even used green lawn mower belts and red Kevlar belts. They worked. I mean a lawn mower takes a lot of abuse. Do as you wish. But once the pullies are polished and shiny, they will rust very quickly and chew belts up fast. I had me pullies changed to solid pullies and tossed the stamped pullies. Good Luck. Stop squealing on each other. No body likes a Squealer.

I just replaced both alternator belts with the Dayco's and immediately the passenger side is squealing, did not do it till I changed out the old one, any thoughts?

 

[Finnegan1008]

I just replaced both alternator belts with the Dayco's and immediately the passenger side is squealing, did not do it till I changed out the old one, any thoughts?

I have found this can be caused by a couple of things:

A - The belts will stretch pretty quickly, and they will stretch way more than you'd think. Because of this they need to checked every so often and need to be pretty tight. I found that belts that are a small as possible are best. The belts commonly mentioned as the right size are too big for my bone stock truck, I now use belts that only go on with the alternators adjusted all the way in.

B- CUCV's (at least mine) don't like to be started up and shut down all the time with minimal run time. If I start my truck and don't let it warm up the drivers alternator will squeal. I believe this is because I have the glow plug resistor bypassed and running the glow plugs will drain down my forward battery. It takes about 15 minutes of warm up for everything to equalize and the drivers side alternator to not be loaded up. Once warmed up the alternator isn't working as hard and the squeal goes away. When your truck is squealing how does you volt meter look? Is it right on the tick mark in the green zone?

I would check the health of your batteries (especially the rear) I bet you are firing up the truck with a weak/ unhealthy rear battery and it's causing that alternator to work overtime. Also I would let the truck warm up and actually drive at least 5 miles every time you fire it up to make sure the batteries get topped off. Lastly make sure your belts are tight.

 

[87cr250r]

I will argue against warming up engines, however. Start them and drive them. Turn it off if you're not driving it. While it's not specifically a problem on the 6.2, in general there is poor lubrication for cams and valvetrain at idle. Keep this in mind if you have an old engine with flat tappets or a new engine with cylinder deactivation.

If your belts are stealing they aren't tight enough.

 

[Barrman]

Gates belts that fit your truck correctly is what works for me. I even did a video about it: