Is alternator failure just that common on these cars, or is there something else that may be at fault here? I've owned GM cars all my life, and I've lost an alternator on just about every one of them, but in the last year, I've gone through 3 on the Corvette (91 6-speed).

When I bought the car last march, it had a new alternator, but when it failed a few months later, I dismissed it because it was a cheap parts store alternator.

I replaced it in the Carlisle parking lot last June with a new Delco. A month later, I replaced that one in a State Police barraks parking lot with another Delco.

Today, that alternator left me stranded, and right now the car is sitting in yet another parking lot while I wait for my 3rd Delco to get here.

I was going to buy something with a lifetime warranty, but not one single parts store in the area has one in stock.

So anyway... when the alternators are working ok, my voltage is steady and doesn't waiver. I'm not putting any extreme loads on it, and the belt seems to be working just fine. Is there something that could be causing me to **** through so many alternators or is it just bad luck?

 

You are using the term "new."
Do you mean a newly rebuilt alternator or an alternator that was never on any car before?

My experience with rebuilt alternators today is don't buy them.
I believe in only top-quality brand new ones. And, most junk rebuilt alternators from the discount stores have a lifetime warranty. After replacing several, I figured that it wasn't worth my time and the inconvenience, even if the alternator was free.
Most quality new alternators have a one to two year warranty.

Another thing to keep in mind is an alternator is a "battery maintainer" and NOT a battery charger. When a battery gets run-down from lack of use, etc., you should charge it with a battery charger before using the vehicle's alternator to maintain the charge.

Tom Piper

 

I replaced 1st alternator at 31,000 miles bought an upgraded alternator. Think it was called Iceberg or something like that; would have to get more info on it. Anyway no problems since. I was told it was a cooling and small bearing design problem. Ike

 

The last 2 (and now this third) alternator were Delco alternators purchased at a chevy dealer. I don't know if they are new or remans, but typically I've had very good luck with them.

My battery seems to be just fine. I drive the car daily and it cranks effortlessly every morning.

 

I replaced 3 or 4 on my '90 in a short period of time a while back, but haven't replaced one in a couple years after getting a brand new one from GM. 120 or 125 amp I believe.

 

I agree with making sure it's not rebuilt. We went through a number of them on our Firebird.

The vette on the other hand is stock. She's got 130k miles on the stock alternator, knock on wood. Oh, and it's a '92.

 

I've also had three in my 91 in the past year and a half so I'm guessing its a common thing.

 

[QUOTE=Tom Piper]You are using the term "new."
Do you mean a newly rebuilt alternator or an alternator that was never on any car before?

My experience with rebuilt alternators today is don't buy them.
I believe in only top-quality brand new ones. And, most junk rebuilt alternators from the discount stores have a lifetime warranty. After replacing several, I figured that it wasn't worth my time and the inconvenience, even if the alternator was free.
Most quality new alternators have a one to two year warranty.

Another thing to keep in mind is an alternator is a "battery maintainer" and NOT a battery charger. When a battery gets run-down from lack of use, etc., you should charge it with a battery charger before using the vehicle's alternator to maintain the charge.


I agree...

I made the mistake of buying a "lifetime" alternator from Kragen auto parts in California 6 years ago. After replacing 3 in a 2 year period and 2 batteries that these alternators cooked, I went to a local rebuilder. The local rebuild still works great and I'm going on 4 years with the Interstate battery.

The guy that rebuilt mine showed me the sub standard parts that most companies use like bearings & brushes that are factory 2nd's. And then they install voltage regulators that are undersized and fail under heat stress. He pointed at the regulator thru the back of my alternator before he disassembled mine and then showed me what he would be replacing it with. The heat sinks alone where twice the size.

My local rebuild came with a 1 year warranty. I'll take that over 3 lifetimes anyday!

 

check all of your grounds;you might be running open ground circuit somewhere.

 

Check the resistor or diode that is on the ac plug sometimes they go bad and let current generated from the ac clutch to enter the ground side and screw up an alternator I have had it happen more than once.

 

Quit counting long ago and I don't know of any "new" alternators. Unless something has changed, the alternator you buy from a dealer is a rebuild as is anything they replace under warranty. However, they seem to last far longer than the rebuilds offered by the discounters. In fact, Corvette Fever or Vette Magazine took a bunch apart years ago, finding the quality of the replacement parts in the GM - AC Delco remans exceeded anything that was out there.

 

If you're willing to do a little adjusting, the alt from the ZR-1 (LT5) is supposed to be far superior to the standard L98 alt.

 

Check the tech tips, couple of years ago I wrote one about this problem and how to install the CS-144 ZR-1 alt to a L98 car.

Only one thing to add to that tech tip: I also added an extra ground strap from the alt to the exhaust manifold after I learned that the 2nd most common reason (1st is heat) for CS-130 alt failure is insufficient grounding. I used a wide battery negative cable for the grounding job. The alt has worked flawlessly for couple of years now. I think I lost about 5 alternators before this mod.

Ps. whats wrong with the forum, it doesnt work with any browser properly? Cant even choose anything from the drop menus...???

 

Sears now sells a totally new alternator.

If you go to Autozone and ask for an alternator, you will probably get a lifetime warranty alternator that will last about a year for about $60. And, after you replace the 6th one for free, you will determine it isn't worth your time.
If you tell Autozone that you want something better than that junk, they will sell you "Gold" series alternator that is brand new for about $120 -- I have one of these that is about three years old, with no problems so far.

There was a time when a rebuilt alternator or clutch was as good as a new one (can you remember when they were rebuilt in the USA)-- those times are gone....the competition and the urge to make a profit has spawned an aftermarket that wants to cut costs even if it sacrifices quality. I won't buy a rebuilt alternator or clutch.
Although, I've been told by several (including a post above), that the local rebuilders can make a very good alternator with high quality parts -- but, you are going to pay more for it, and it won't have a lifetime warranty.

Here's my next alternator:

http://www.mean-green.com/products/alternator.html

Notice it doesn't have a lifetime warranty.


Tom Piper

 

BTW. dont waste your money on the Iceberg -kit for CS-130. I did and it didnt last any longer than the stock unit. CS-144 has all the faults of the CS-130 fixed and you never hear anybody having problems with them.

 

Today or tomorrow I'm going to test the voltage with the car running at the alternator and at the battery. I want to verify that the cable going between them is doing its job properly.

I love a mystery.

 

big question is do you have an amplifier. if you do then you need to get a gell cell battery and put it in your trunk. not sure how they wire them but its about 60 for labor and wires and it will take all the excess power and store it in the battery till the base hits hard. i did that and was on my 4th and never had a problem with it again.

 

If you have the boost fan out front it's controled by the switch in the head just below the alternator. There are aftermarket switches that will turn on the boost fan sooner than the stock 230 degrees. This will help keep the temp down a little under the hood. Heat is the #1 alternator killer.
I'm on my 3rd Pep Boys lifetime. The last two were brand new. I think the car sitting up and the battery getting weak killed one of them. The other one went when I was working the summer in FL.
I almost went with the local auto electric rebuild in 96. The guy said he could put 160amp truck parts in it. If I was at home I think I'd go that way.
The guy said they were seeing problems with everything GM either front drivers or vetts and firebirds without engine driven fans since they run so hot under the hood.

JS

 

Take my advise, unless you want to spend your lifetime replacing your alternator from [fill in favorite auto parts store here] with a lifetime alternators, just go to:

http://www.powermastermotorsports.com/

I used to replace mine every few months until I got one of these in there. No problems after many years

 

Your IROC alternator hasn't given out yet

I've replaced my 1990 Firebirds at least 12 times in a 4 year time frame.

The Corvette since I own it replaced it twice.

BTY my Firebird and Corvette alternators are the same....