I've run into problems that may be related, so I wanted to bounce some ideas off of you guys. Lately on startup, I've been hearing a crazy squeal (like a belt slipping). Takes a minute or so and then it goes away. But I'm also hearing kindof a noise that's like some sand and small pebbles in a dryer sound that's happening all the time but you can hear it most at idle. Fast forward to today and I started my car and saw the volt meter go fairly high (like16/17 volts) for a minute then it dropped to like 11/12 volts and the voltage light starting coming on faintly. I'm thinking that maybe the alternator's bearings maybe going causing a funny rattle-like sound and the belt to squeal and has now just gone altogether. I'll look at it this weekend, but I was wondering what you guys thought, thanks.

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'87 GT 5-speed

Remove the belt and spin each pully by hand. You will probably feel roughness in one of the pullys, which is not good.

The squeal at start is your belt slipping. After start up when it squeals your voltage is low. Usually what happens is when the engine RPM gets low enough, the belt starts to grip, and when that happens the squeal goes away and the voltage gauge comes up to where it should be.

re: The way high voltage after start up along with the dim voltage light. Sounds like a voltage regulator starting to go. Unplug and replug the alternator plug a few times first to see if that clears the problem. If not look at replacing the voltage regulator in the alternator.

My A/C was making noise like the compressor was loose, turns out it was. It's hanging by one bolt, hopefully until tomorrow afternoon, when I plan to install bolts I bought this week.

I had the squealing at startup, then the lights and everything kept getting dimmer, then the battery died. Replaced the battery, everything runs fine, charges like it should, also no squeal.

I had to remove pieces of belt from the compressor and alternator, etc. The compressor wouldn't turn because pieces of belt were stuck in the pulley.

I had a Volvo years ago that had a rattle from the alternator. I was told that it was actually an electrical problem causing that noise; that it was the failure of one or more diodes, it would result in the alternator producing only about 10 amps, and IMHO it was likely caused by jump starting.

So, I happened to have a rebuilt Duralast alternator. Apparently tightening the housing bolts (4) was not a requirement. 1 was gone, 1 was completely disconnected and held by the heat shield, the other 2 had about 1/4" gap, so this caused a little problem inside the alternator. I could probably have just fixed the broken wires and stuff, but I decided to just go with a new one...which was another fiasco trying to install. I thought the new one should have the correct pulley, but apparently you have to replace it. That's not a problem, but the guy at Napa offered to do that for me. He was also nut-tightening challenged and halfway to work the pulley was starting to rattle and I had to get towed. WTH. I'm more upset with myself for not checking it...grrrr...

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'87 GT 5-speed