So I just recently bought a Vette- 98 automatic, which is currently having that automatic replaced, but that's irrelevant to this post..

There is a particular squeak coming from the front of the engine. I have already replaced the main belt tensioner (it was well worn and cocked a little sideways), and have an idler pulley to be put on once I get car back from shop. But if that doesn't stop the squeak I was going to replace alternator next (even though it's still charging fine).

I was a little shocked when I looked up the price from Autozone, and even more shocked when the GM parts guy told me what the general wanted for it So I've been searching the forum for alternator info and have found that not putting the right unit on the car can cause the PCM to post error codes, even if the alternator is charging. So that has me a little concerned about buying a unit from Autozone, not knowing for sure if it's proper for the car until installing it & seeing if the car yells or not. Does anyone have any experience with buying a reman unit from Autozone or other parts store for their C5? Any compatibility issues?

Also considering just pulling it and taking down to my local Alternator & Starter shop to have the bearings replaced, since the unit is still working.

Of course my squeak could still be one of the other components..

 

I would be more suspicious of the harmonic damper (main pulley) on the crankshaft given the age of the car. As for the alternator, I got stuck on the road once with my Suburban and went to AZ for the alternator. The first one he pulled out squealed when I spun it. The second one made another sound. The last one they had to fit had a buggered up pulley so he swapped the pulley with mine and I went back to the car on the side of the road to install it. That's when I found out the threaded holes were stripped in the casing

Check the crank pulley and if its the alternator and you have a reputable shop that will rebuild it, get it rebuilt.

 

If it turns out your OEM alternator bearings are indeed bad, I'd recommend bearing replacement. Under no circumstances would I exchange my OEM alternator for a rebuilt unit. If and when my alternator needs work, I'll have it repaired by a local rebutable specialty shop.

 

Yeah, I never bought a rebuilt that lasted very long.
But, if you do replace yours, be SURE to get the same part number; they changed in '01, and according to the guys here, the later 145 amp models WILL throw codes on a '97-'00 car. Just check the label on the underside of the alternator.

DG

 

I had someone explain that the internal resistance of the later alternators is different than the early ones. They had a different manufacturer. As far as I know, my 04 coupe throws the occasional "Charge System Fault" upon startup but this is apparently normal. With this car, anything not changed in the database, looking for a certain resistance is enough tattletale to trip a code, even thought there is nothing wrong with having the later alternator on it.

In other words, don't sweat it if it throws a code. As for running an AZ part on my vette, consider it before doing it. Those could have anything ranging from mouse droppings to cracks in the case, no kidding. I would find a reputable supply house to get my parts from. Don't forget the supporting vendors or even Rock Auto. Worth pricing around. I would personally put a GM part (GM reman part on it) and keep my core. Its probably 50 more but you'll always have your stocker. My .25 cents.

Cassidy

 

I Worked at Autozone for a few days long ago and lets just say I would NEVER put anything from Autozone on my car unless you enjoyed always taking that part back for a new one. Had one guy put 6 Autozone alternators on his car before he had one that worked... for a week lol...

Second I had that same sqeek and thought it was the tensioner and the idler and my technician at the shop I run said it was just the belts. Replaced them both and never had a sqeek again. Cheaper than all the other things it could have been. The belt still looked good to but it was bad.

 

You want to know how cheap the manufacturers are? I designed an alternator assembly machine for a "major manufacturer" and when we were in the buyoff stage they had two different sealed bearings. The maroon seal and the black seal. I asked what was the difference between the two and was informed the black was the heavy duty for the higher output alternator. What was the price difference .02 cents. I know pennies add up but that was plain wrong.

 

Thanks for all the replies. I'll definitely go ahead and change the belt while I have it off to see if that stops the squeak. Belt doesn't look terrible but certainly not new either.

As for the alternator- I've seldom had much luck with GM alternators, originals or bebuilts from AZ and the like. I've changed them out on two Cutlass Supremes (multiple times), a Regal, and two S-10 trucks. The best one I had was on my 92 S-10 that lasted from about 35K when I bought it to over 100K when I traded it in. HOWEVER, even on that unit I did have to have the bearings replaced at some point. I'm currently not picking up any charge system codes on the vette and would prefer to keep it that way so I think I'll stick with just having the bearings changed if it's needed.

And although it sounds like it's up top somewhere, the squeak could also be from the secondary belt that drives the A/C... And that doesn't look fun to get at without the car up on a lift- which I don't happen to have

 

Nope, it is easy to get to just sitting on the ground. You have to remove the serpentine belt, then just rotate the tensioner for the A/C belt and it comes off and goes on even easier than the serpentine. 2 minutes start to finish for that belt ....

 

Had the same issues, change both the tensioner and the idler, still squeek when I started the car. Change both belts to Gatorback Only issue you have to get them at Autozone

Gatorback Poly-V w A/C 4040420 -Autozone $14.99
Gatorback Ploy-V alt & P/S 4060798 –Autozone $23.99

 

 

just curious, how many miles on the car? and is this the first time you are experiencing anything "weird" on your alternator?

 

Car has 112K on it and I only had it 4 days when the tranny gave. Car won't be out of shop until Friday or Monday. The squeak was there when I bought the car, but I haven't experienced any problems with alternator. I'm only guessing that the alt bearings could be the squeak cause but from info I'm getting sounds like it could just be the belts.

Speaking of the belt- interesting part of buying the car... when I showed up to look at it the owner backed it out of the garage into the driveway and shut it off. I began looking at the car, popped the hood, and first thing I notice is that the belt is not on the alternator. I pointed it out to the owner and she's flabergasted, doesn't know what to say. So I volunteered that if she could find me a socket set or the right size wrench that I'd put it back on for her. She gladly accepted and ran to neighbor to borrow a wrench. Even without a diagram I had the belt back on in just a few minutes (then verified routing per the diagram in the owner manual). Cranked car and all was fine- except the tensioner was cocked a little from wear and the squeak was there. She said she hadn't driven the car in a couple of months so I figure the belt was stiff and jumped off when she cranked it. I can only imagine she felt like when I pointed it out to her.

I stopped at AZ this evening to see if they had belts and was told the options were the gatorback or the duralast but they would have to order the gatorback. I didn't order them, may find an alternate source but will probably go with the goodyear.

 

Although I've never bought those kind of parts from an Autozone, I know someone who went through lots of things for an old Ford from AZ. Contantly returning them for replacements and the worst was their brake calipers and rotors.
I did buy rear hubs for my '99 from them but they were manufactured by Tiemken

 

you may be experiencing the same problem i just had on my c6. there's a voltage regulator on the back of the alternator. the alternator shaft sticks out a bit in the back when you pull the back cover off. there's two little magnets on the inside of a collar that ride on the end of the shaft when assembled, and that's where my squeak was coming from. btw, my alternator still put out the proper voltage and everything, and the bearings were fine, just had an annoying squeak to it that slightly resembled a belt squeal. hope this helps.
-mike

 

Take the surp. belt off and start the car that will let yoy know if its in ac or maine drive and go from there. It will give a 1636 code just reset when your are done.

 

Another thing you can do is to just spray the belts with silicone spray. If it is the belts, the noise will stop immediately. Unfortunately, it will probably come back after a while.

 

 

My 1999 did the same thing, I thought it was the alternator bearings. It was the Goodyear Gatorback belt, which was new. I too replaced all tensioners, idlers and belts and still had this squeak.

I bought a new alt from Autozone, changed it in the parking lot and STILL had the squeak. As soon as I got home, I yanked the belt and it stopped. I didn't like the tread pattern on the belt and put on a new Dayco that I had (Dayco pattern is the same pattern as GM) and it stopped completely. Some C5 owners swear by Goodyear belts but I'll never buy another for my Corvette. I don't think that Goodyear makes a Gatorback belt that is the same size as what our cars require. You either have to go a little bigger or smaller. I have no idea which the guy at the parts counter gave me.

This was several months ago and my car is quiet as a mouse, minus the squeak of course.

Also, make sure that both idler pulleys spin freely once tightened. Sometimes if not aligned properly, the dust covers (2 little metal rings, one behind, one in front) will stop the pulley from spinning freely and will cause a squeak.

 

I replaced the factory spring loaded belt tensioner with a Comp Cams 54021, which was designed to keep the belt from coming off (taller pulley sidewalls) at high RPMs. Unlike the stock unit, there is no spring and desired belt tension is added with a torque wrench. Now the belt tension remains perfectly constant and true and spins like a swiss watch. No more flying belts with a side effect of no more pesky belt noises.