Please bear with me as this story goes back a ways. Several years ago, I replaced the OEM alternator on my Formula with an Advance Auto unit. I'm pretty sure the replacement was a 105 amp unit. I noticed immediately that the mechanical resistance was higher, but I thought that the bearings would likely break in and free up. I had a little problem with belt squeal but not too bad. I now attribute this to the fact that I kept it in a garage because after moving it outside, it developed a much worse squeal problem, especially when the humidity was high, like when there was dew on everything in the morning. I tried tightening the belt, but this would only work for about a week, then the squeal would return. At the time I suspected a bad alternator, so I took it back and had it tested. They deemed it bad and replaced it. OK, great. I had a bad alternator. They couldn't seem to get it up to proper speed, so I thought that the bearings may have been bad. The new one behaved exactly the same. OK, not great. And, yes, the pulley has the correct number of grooves.

Second problem. Whine. The new one and the first replacement also have quite a bit of whine. I'm pretty sure that the whine is from the alternator because of what happens when I first crank it in the morning. The alternator doesn't move at all until the belt dries out a little and starts getting better traction. I have witnessed this. Takes about 30 seconds or so. During this 30 seconds, I can hear the belt start to squeal slightly, then slowly get louder. As it gets louder, the voltage meter reading increases. Then the squealing stops, at which point the voltage stops increasing. I also hear a whine that increases in volume and frequency as the voltage (and alternator speed) increases. The whine is non-existant when the engine is first started, so I strongly suspect it's the alternator.

I suspect that for whatever reason this alternator has too much mechanical resistance for the Fiero. Not sure whether it's the engine bay heat causing the belt to stretch or what. But this alternator seems to have too much mechanical resistance and more output than needed. I can pretty much run continuously with max electrical load at idle. Nice, but not really necessary. Has anyone else had this problem, and have you done anything to fix it? I have thought of two things to try. One, an underdrive pulley. But I'm not sure how the 105 amp unit would behave at idle. And, can you get an underdrive pulley just for the alternator? I don't really want to change the speed of all the accessories. Two, since the only thing I can find in the parts stores are 105 amp units, rebuild mine to 85 amp specs. I would prefer this option since it would retain the stock pulley and belt. Comments?

Have you tried getting a different belt? I hear that the Gatorback brand ones are the best. I upgraded my SI one in my '87 to a 130 amp (rewired) CS one. Mine does not squeal and I even have some slack in it, about 1 inch. You can tighten the belt all the way or you will damage the bearing in the alternator or water pump. You should also make sure that all of your pulleys have a matching set of grooves and that they are all lined up. I had to tighten my harmonic balancer to get them al lined up. I think yours is squealing because your belt might be glazed. I hope you find a solution. Good luck.

Just from what I've read here on the forum, most aftermarket rebuild alternators are junk. Safest bet is to buy a new Delco unit.

Secondly, in your post above, you never mentioned putting a new belt on, it's likely that you belt is "glazed" providing insufficient grip. If you tighten this type of belt to eliminate squeal, you over-load the bearings bringing them to quick failure (usually the rear bearing will go first in this situation). Lastly, roller bearings in the alternator don't require a break-in period.

LOL, I posted before seeing response above.

[This message has been edited by California Kid (edited 03-17-2005).]

Yeah, in my humble opinion, your problem isn't the alternator - it's the belt.

Goodyear Gatorback belts are the best. I won't use anything else.

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Patrick W. Heinske -- LZeitgeist@aol.com
1988 Red Fiero Formula Convertible

My car really punishes the V Belt with my pulley arrangement (does a 180 turn over a tensioner pulley), it will shread a Goodyear Gatorback in less than one summer. Best belt I've found is made by Dayco, it stays together, and will last up to 3 years.

O.K., perhaps I should clarify - in my experience, Goodyear Gatorback belts are best for V6 applications - I haven't used a Gatorback on a 4-cyl w/a tensioner.

I guess I should have mentioned that I've gone through three belts during this time. Each time I replaced the alternator, and one more time to try to stop the squealing. I don't think any of them were a Goodyear Gatorback. I may give one of those a try.

[This message has been edited by Formula Owner (edited 03-17-2005).]

I have the same problem with my V-6, in the mornings with any moisture (Florida Humidity)
I have replaced and tightened the belt yet comes back Sceaming in a few days (Annoying)
I will try another belt as ppl have mentioned.
Glad you brought it up Formula Owner

I forgot to ask. Where can you get Goodyear Gatorback belts? Do you have to go to a Goodyear store?

I've found them at more 'performance-oriented' parts stores, rather than the usual places (Advance Auto, Pep Boys, AutoZone).

(The place I get them from locally is Steve Ashworth Performance, but it doesn't sound like that's gonna be a help to you...)

Another thing, no one mentioned above, that could cause belt failure is a seized water pump, these will also squeal before they completly seize up.

quote Originally posted by Formula Owner: I guess I should have mentioned that I've gone through three belts during this time. Each time I replaced the alternator, and one more time to try to stop the squealing. I don't think any of them were a Goodyear Gatorback. I may give one of those a try.

If the belt is properly tensioned and slipping so bad it can't even turn over the alternator, then there's something seriously wrong somewhere. (Especially if it's a serpentine belt.. They rarely slip).

If the alternator isn't turning as the belt turns over it, then the alternator bearings are probably toast.. I had the alt bearings sieze in my 88 Duke with a serpentine belt. The belt held so good that the drag from the frozen alternator caused the engine to stall.

Before replacing anything, I'd check with a straight edge to make sure all the pulleys line up. If any the tensioner or alternator or AC pulleys are a bit out of place, it will put stress on the belt and possibly the bearings.. Look for one pulley either set back further , or extending out further than the others, or look for a pully that's at an angle (Not square with the others). Check the belt with the car running.. See if it's tracking true or if it's squirming.. (That's another sign of misaligned pulleys). If the pulleys are out even a little, it can cause problems.

If that's all good, then pull the alternatior.. If you should be able to twist it easily with two fingers.. A hard spin should have the shaft continue turning a bit more after you let go of it.. It it's bad, Get a replacement from somewhere else !!!! Whoever is rebuilding them isn't doing a very good job.

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1988 Fiero Coupe 2.5L
1990 Trans Am GTA 5.7L

[This message has been edited by Poncho Jim (edited 03-18-2005).]

quote Originally posted by avengador1: Another thing, no one mentioned above, that could cause belt failure is a seized water pump, these will also squeal before they completly seize up.

or they will squeel just like the alternator till the bearing hollows out and coolant starst shooting out of the engine (been there)

I would recommend you take that alternator.. buy an iceberg upgrade (new rear housing with upgraded bearing) and that may fix it.. I think its low quality bearings in the alternators

I had the same situation for about a year and a half my car would skeek real bad at starttup for about 10 seconds. My AC went out and I had the compressor changed because it was bad the other one was locked up that was part of my problem. It didn't skeek for a while then it started it again. It sounded like it was the ac belt I replaced that with no luck. I never thought anything else about it. A couple weeks ago my alternator statred going out. It was putting out voltage (thank God) but just enough that the battery would go dead. The top bolt was froze up on the alternator so I had to take it to a local shop to get it replaced. They took the bracket off to get the alternator out and they drilled the old bolt out and put a new one in but at my request didn't retap the aluminum bracket jsut put a nut on the bolt so I won't have that problem again. I hate aluminum stuuf. Anyway so they put in a Napa alternator I love Napa parts and I put a gates belt from Napa on it. I love Gtaes belts that is all I use I think they are the best but that is my opinion of course. To make a long story shorter the car doesn't skweek at all now on startup and it runs better thanks to the Napa alternator. My old alternator the bearings were bad in it.
I hope this helps you out.

quote Originally posted by Poncho Jim: If the alternator isn't turning as the belt turns over it, then the alternator bearings are probably toast.. I had the alt bearings sieze in my 88 Duke with a serpentine belt. The belt held so good that the drag from the frozen alternator caused the engine to stall. Before replacing anything, I'd check with a straight edge to make sure all the pulleys line up. If any the tensioner or alternator or AC pulleys are a bit out of place, it will put stress on the belt and possibly the bearings.. Look for one pulley either set back further , or extending out further than the others, or look for a pully that's at an angle (Not square with the others). Check the belt with the car running.. See if it's tracking true or if it's squirming.. (That's another sign of misaligned pulleys). If the pulleys are out even a little, it can cause problems. If that's all good, then pull the alternatior.. If you should be able to twist it easily with two fingers.. A hard spin should have the shaft continue turning a bit more after you let go of it.. It it's bad, Get a replacement from somewhere else !!!! Whoever is rebuilding them isn't doing a very good job.

The bearings are no different from when they were new. The alternator turns after the belt dries out. I do think that the bearings are poor quality. Spinning the the alternator by hand, the bearings seems too tight. Or possibly something else in the alternator is causing too much friction, like the motor brushes. Checking the straightness of the pulleys sounds like a good idea. I'll do that. I don't think, as someone suggested, that I have a water pump problem. I've replaced it (a few years ago) and it had no effect on the alternator. Yes, a water pump failure can cause squealing too, but I have witnessed the belt moving over a stationary alternator pulley. After reading other threads here regarding poor parts from the discount stores, I'm beginning to feel that I just need to bite the bullet and buy a Delco unit. They are sure proud of those things though.

To va441975, my current belt is a Gates from NAPA. It still squeals.