Hey guys, I recently did a 3g upgrade on my 1989 f150 5.0 AOD 2x4. After the swap when it starts the belt squeeled for about 2 seconds, every time. I bought a new belt, thinking that it was the problem. It was getting close to needing it because it was dry rotted anyways. Still squeels. I tried putting my old (65A) pulley on the 3g, same result. I noticed a spark when I first started the truck from behind the Alt, so I disconnected the charge wire to insulate it better. I tried starting it without the charge wire and no squeel, so I know it's the Alt having more drag from the start.

I beefed up all the charge wires\grounds (all 4 awg) 3 wires going from the + post to the Relay post that everything is fed off of, including the charge wire to the alt (with fuse of course). I tried the charge wire without the fuse (only as a test) and it still squeeled. I have 2 4 awg grounds on top of the stock grounds run, one directly to the Alt case, one directly to the coil.

I've done all the trouble shooting I can think of, and the only thing I can come up with is the tensioner, which ironically I just put a new pulley on(before all this BS). I was curious to see if anyone else had the squeel problem and if it was indeed the tensioner. Also, if is poissble to clean\respring the tensioner itself so I don't have to replace it? The belt is well within the Range indicator on the tensioner. Thanks for any input.

 

What do you want to clean on the tensioner? It's 3 pieces: the pulley (with sealed bearings pressed in), the arm, & the spring. If it moves to full-lock when you remove the belt & release the arm, then it's working. If the arm isn't damaged, there's no reason to replace the tensioner. If the pulley spins free & silent, then it's OK.

Pulleys can collect deposits, film, & varnish, so use a wire wheel & brake cleaner to clean all their grooves, and wash the belt with warm soapy water to remove any contamination.

 

The old pulley was noisy and the bearings were bad inside of it. I'm thinking that the spring isn't providing as much resistance as it should, is there any test for it? As it squeels I can see the tensioner rotate up until the squeel goes away. I've cleaned the pullies with a wire brush already, I'll try the brake cleaner and see if it helps.

 

Measuring the belt's tension requires a special tool. I've only found one mention of the tensioner's specified force, and that's 51-69 lbf, but it doesn't say where or how to measure that. And I doubt there's anything wrong with the tensioner's spring anyway. I think it's strictly belt or pulley contamination. I know that's why mine squeals for a second every time I start it.

 

Lol, cool cool thanks for the input, if there's anything this truck has taught me, it's to research everything before I buy something, otherwise I'll just end up throwing money at it. Soon I hope to be doing a saginaw Ps pump conversion so when I do that I'll pull off every pulley (that I can) and go to town with a wirebrush. One thing I noticed this morning is that at idle my smog pump pulley wobbles a little bit, nothing crazy, but just enough to notice. I just replaced the smog pump and it's still within the 500 mile break in. Think that pulley might have something to do with it?

 

It's possible, but not very likely. I guarantee you this smog pump & pulley are in worse shape, and this truck's belt doesn't make ANY noise:

 

I had a squealing serpentine belt on my 93 F-150 5.0. The pulley and tensioner were OK so I replaced the belt with a Gatorback brand. No more squealing.

Santiago

 

It actually ended up being the tensioner, I bought a new one and the problem went away. Already had a new belt, and all my pulleys were clean, so this was the next step. new pulley has been on for over month now and havn't had a single squeal!

 

thanks for updating it's good to read a thread and end up knowing what the fix was.

 

Mine is a '94 5.0l 4x4, and my mechanic put on a new tensioner & belt in early January -- something started squealing intermittently a few weeks back and when he took a look the new tensioner wasn't rotating in the proper plane, though it was mounted properly. Because of the out-of-plane cant, the edge of the belt was actually getting worn slightly. He noticed that tensioner was made in China and he'd gotten it from his regular parts supplier (not Autozone, think it was O'Reilly), so he replaced it for free with a different one (and a more expensive option) that was made in Canada from a different local parts house -- so far, no squeal.