Alternator Failure

I have a 96 Cougar with the 4.6 liter V8 and about 224,000 miles. During the last year I have gone through 4 alternators, the last one lasted for 6 weeks. Autozone has told me next time there is a failure, they will no longer honor the warrently.

They claim something is wrong with the car. I switched batteries recently so do not think that is the problem.

I talked to my mechanic and he thinks Autozone just has a batch of bad alternators.

Any ideas?

It would be of help to have someone do a postmortem on the alternator to see what failed. The problem is that if you open the alternator Autozone will not honor the warranty. When you put in the next covered alternator, have an autoelectrical shop diagnosis your battery/charging system. Have the shop document the salient parameters. Then if this alternator fails, they can do a postmortem and give an opinion on why the alternator failed. They would be a resource if you had to take this case to small claims.

Hope that helps somewhat.

Could be the AZ alternator or it could be a problem with your car… that said, a friend that used to work at the 'Zone told me that they have a 40% return rate on their rebuilt alternators. Even on the lifetime units.

Most auto part stores get their rebuilt parts from the same sources. Generally they end up getting more of a repair than a rebuild. They fix the primary problem, but don’t replace other worn parts. Chances are good, you have just not gotten a good replacement. You might ask them where their warranty statement is limited? That said, there could be something else wrong. but my money is still on the rebuilt.

I’d bet it is the quality of the rebuilt alternators you are getting. I used to get mine from NAPA with the lifetime warranty but I was having to replace them so often for one reason or another, I gave up. The only rebuilt I will use now are AC Delco new or rebuilt. They have all new wear parts and haven’t had any trouble anymore.

I doubt you’ve gotten a batch of bad alternators. Considering the age and mileage of the car I think you have a problem in the alternator wiring.
Has AutoZone actually tested these alternators and verified that they’re really bad? I assume they have, so if this is the case…

The wiring between the alternator and battery has several junctions, connectors, and fusible links in the circuit. Age and heat can cause a bad connection at any one of these points. This can cook an alternator over time.
If AZ is not testing the alternators and simply taking your word for it that they’re bad then it’s possible the alternators could be good and not charging because of a fault in the circuit that excites the alt. fields. This means the dashboard alt. warning lamp. A faulty bulb or on again/off again connection can cause the alt. to fail to charge.
The little red light must always illuminate and the circuit must always be good for the alt. to charge.

To verify a bad alt. turn the key to the RUN position (engine not running), verify the red light is on, and touch a small screwdriver to the alt. pulley. You should feel a magnetic attraction in the screwdriver tip. If not then the alt. is dead more than likely.

For what it’s worth, and to give you an idea behind the connection theory, my daughter called me this evening from the side of the road. Her Mitsubishi just flat died on her at 40 MPH without a hiccup or sputter. After getting there the car started right up and ran like a top for me. I let her take my Lincoln and I drove the Mitsu on home with no problem.

After thinking about it a while I went out there, removed the fuse/relay box lid, and pulled the fusible link that controls all engine electronics and the fuel pump. These links are small square boxes rated at 30 amps. I pried the plastic top off and by a quick visual the link was good. However, under a magnifying glass the link showed to have a very tiny (less than ball point pen tip size) ball of solder on each side. This tells me heat was melting the solder due to age and current load. A light touch with a pocket screwdriver caused the balls of solder to fall off. No doubt with a bit of driving heat would have finished it off and it would have quit for good.

The reason it started for me when I went to get the car is because the link had cooled, along with the solder, and the connection was made again. How many times it would have survived this is anybodys’ guess. I had some extra links and the car has been fine ever since. This kind of problem was fairly common in the old days with glass fuses.
The point here is that most problems often have a simple solution.

One thing that can cause this kind of thing to happen is if the battery sense lead to the alternator has a problem. If it gets grounded out somehow and the alternator things the battery voltage is low it will put out a high charge to try and keep up with the current demand it thinks the electrical system is demanding. If that goes on continiously it can damage the alternator. If the alternator gets real hot and stays that way the problem may be with the sense lead. A good shop will be able tell if there is a problem or not with any of the alternator leads that may be causing this trouble.

My 97 lincoln ate alternators lots of them cheap ones… expensive didn’t matter the shop was putting them in and thought it was ford poor quality.
Ulitmatley that wasn’t the problem it was the the belt tensioner. If your tensioner is bad so the belt isn’t straight it will wear out the alternator. Very hard to track because everything will test and look fine good to go right? nope.