Belt squeal (while accelerating)/alternator question

[59840Surfer]

I've also had a heavy-duty fan thermal drive cause this too.

At first start-up, the oil has migrated to the wrong area, and that in effect locks the fan up to the sheeve.

Then with the alternator trying to make up for what you took outta the battery at start-up, it all adds up.

If you want to eliminate the alternator from the load - unplug the modular plug --- not the B+ Battery wire and start the engine and listen.

If you want to eliminate the thermal fan, just remove it and you'll be able to isolate the noise that way ....

It would not be a big surprise if the alternator sheeve got hot when you have both the fan and the alternator trying to get their full power from a single belt.

 

[59840Surfer]

You do not need to change the wire.even after the squeal is corrected. Stay on task fix the squeals. Maybe the angle of your pics,but looks like an alignment issue. Pay attention to what fastvsays he's very knowledgeable your heat is from the friction of the belt slipping on the pulley, put a penny on your finger rub it on your jeans fast and hard ,it will get hot. The belt slipping across the pulley does the same thing. Quit changing alternators they are not the problem,and everytime you change a part you add a new piece into the equation.

How many years did this vehicle NOT have alternator/belt noise with that wire? This is a false flag - so leave it alone.

 

[Ricko1966]

Hi all! I have an 84 scottsdale with a stock 305. I have been fighting with a squeal that is most pronounced during acceleration. I bought this from a buddy in a different state and have owned it about a year. The squeal would come and go but now it's here to stay. Here is what has been done:

1. New belts before I bought it. I'd guess the truck has around 5k on the belts

2. Checked tightness of belts. I can twist them 90 degrees but cannot pull them on any of the pulleys

3. The battery gauge in the truck moves when it starts to squeal but I didn't notice much of a different on the multi-meter (probably need to test again)

4. It sounds like it is coming from the alternator. The one in the truck is 66 amp from 2002 so I replaced it. I bought a 78 amp rebuilt unit from Autozone (running a new head unit, 2 channel amp, 6x9s and powered sub....installed last week). The fan on the unit looked like it wobbled when you spin it. It was tight but the fan had a wave about it. I installed it to see and the squeal was the same. The alternator pulley/fan was hot and the belt was hot (only ran 45 seconds).

5. Today I replaced the new one (installed yesterday) with the 94 amp unit from O'riellys hoping that the fan was bent and that was the cause of the squeal. The sound is the same. The pulley gets hot and the belt gets warm.

Is it possible it's the alternator and I got two bad ones? I wouldn't think it should be getting hot...especially after running only 45 seconds.

I'm about to start eliminating belts (within reason) to see if I can narrow it down.

I just reread this, take off the belt,make sure the alternator spins free then put on a new belt. If it's been squeeling this long I'm betting the belts glazed. There may be more than that,but you're never going to get a glazed belt to stop squealing.

 

[dec322]

Thanks for the help everyone. I drove the truck around yesterday without the belt on the a/c compressor and there is no squeal. I should have started this project by removing belts but the heat on the alt belt and pulley grabbed my attention. It’s kinda weird because I didn’t have any issues with the pulley and belt getting excessively hot/warm yesterday.
A few points of clarification for future reference:
1. I mentioned changing the wire on the alternator because I’ve moved to a higher amp alt. I’ve read on the forums that a thicker wire is necessary to get the full benefit of the higher amps. I did not necessarily think the old wire would cause a squeal but did wonder if it would cause heat.
2. I’ve put 4K-5k on the truck in the last year and the squeal was intermittent….rare, in fact. It was only after my battery died (1 year old battery) that I started having a continuous squeal on acceleration
3. It would seem my issue is the a/c compressor pulley (or pulley belt). I am running the truck without it as it doesn’t work anyway.
4. The new problem is I accidentally overnighted the negative bolt on the battery and stripped the bolt hole so I can’t get a super tight fit. lol…dumb on my part

 

[Buck69]

In addition to heat, location of noise and volt gauge movement was also mentioned while the squealing was happening?
May want to unplug the clutch for the compressor if you haven't already. Noticed it wasn't in your photos.
Glad to hear you have it figured.