Alternator Light with Squealing

[Tango]

I'll check voltages tonight, but I had an odd thing happen the last two days...

I've been using my 81 Fiat Spider (FI) more or less daily all summer, which is great. Yesterday, when I started it, there was a squeal from under the hood. It didnt sound like fan belt, more like, I dont know... a bearing or something??/ It didnt repeat on the way home last night.

This morning, the alternator red light is on when I started the car. Once up to road speed, the light was still on but dim. Just revving it in the driveway did not change intensity.

As I said, I'll check volts and amps but can't do it til tomorrow night earliest, and I need to order a replacment alternator, if that is what I need, to coordinate with a trip through the States Saturday (i pick parts up in Niag Falls NY -- save on brokerage and courier fees). So I need to make a quick diagnosis, but with the price of alternators, I dont want to change it just in case.

So any thoughts would be welcome. Sounds like an alternator about to fail?

T

[So Cal Mark]

bearings don't normally squeal unless they're seized. They usually rumble as they begin to fail. My bet is the belt is loose or covered with coolant or oil

[azruss]

the issue with a slipping belt is it polishes the pulley and makes grip a problem even with the right tension. they have belt spray that helps. Need to rough up the v-track with sandpaper in the worst cases.

[TX82FIAT]

Ageed, sounds like a belt. check to make sure the belt has about 1/2 inch of tension when you press on it. Sometimes the belts stretch a little after install and need to be re-adjusted. if the car has been driven a lot this summer where it sat over the winter it could just be time for a new belt. i would replace the belt before taking sandpaper to the v-track. Quick and easy to change the belt and you can pick up a new belt for $10. If it is the alternator you are going to want a new belt anyway since belts tend to wear into the new pullies. You might have a new alternator and still have a sqeal from the old belt if not replaced.

[Tango]

Good ideas. I will check ASAP. It's a fairly new belt, but the car sits for months through the winter. I can't recall if I put it on when I did the timing belt or with the water pump last year. Less than 3,000km on it in any case.

T

[majicwrench]

With engine OFF put thumb on fan on front of alternator and push. If you can spin alternator like that, belt is too loose. Tighten belt till you just can't make alt fan move with thumb. Too tight hard on bearings. No need to change belt with new alternator. No need to sand pulleys. Do not spray with belt crap.
Keith

[Tango]

Tension of belt seems okay. Coming home with headlights on, turn signals hardly flashed. Battery voltage is down to 12.1V with engine off and lights on. With engine running voltage across battery is only 12.0V. Just recently I had tested it for another problem and it was something like 13.5V when running.

T