I have a completely stock 1989 Pontiac Firebird Formula 350 that we bought new. The car has gone through about 7 new and reman alternators since new.

Dont think battery condition is an issue here.

Has anyone else had this problem? Is it a design flaw? Is it overheating? Have not had them torn apart to see what failed. Most were reman alternators. Have heard the bearing whining before some failures. Has failed with fewer than a few hundred miles of use in past.

This last time took it to local shop that rebuilt with all new heavy duty parts.

Any diagnostic ideas to pinpoint problem if it is not a design flaw? If it is a design flaw andy suggestions for a better replacemnet or part that will fix current design?

Anyone with any knowledge on this please weigh in.

 

I'd like to know if there is any definite reason, but from what I understand it's overheating mostly. They are too small for the needed demand. Mine just killed the second alternator in a week, but it's been crazy hot here in GA.

I'm just going to get a late CS-144D if I have to buy an alternator.

 

You should try taking it to Auto-zone. I believe they have a tool to test the electricity and tell you what the problem is.

 

Get your battery tested. If your alt is trying to charge a battery with a dead cell, it won't work out for you. Also, make sure you'd battery is fully charged before you finish installing the new alternator. That way the alt isn't trying to jumpstart a dead battery.
And lastly, try going with a 140 (if you haven't already) and see where that gets you.
If all else fails, you might need a bigger battery. Hope some of this helps. And DrexRS is right. Autozone, Advance Auto Parts, or most other part stores will test it for free.

 

upgrade the charge wire from the alt to the batt
also make sure to use a good body ground is near the batt

other than that check your fans maybe one is not turning freely
or up grade to a higher amperage alt a 140A is easy to find at a junk yard
a sensor may be keeping the fans on all the time?

 

I think heat does has something to do with the alternator going out. Mine took a dump on the way home from The Pontiac Southern Nationals last weekend. It was close to 100 degrees out.

 

While heat is a reason for failure, these should operate just fine within those temperatures as alternators were designed to withstand more than that.....
The most definite answer I can give you is, for some reason your alternator appears to be at 100% demand for it's entire running time. If your battery is not charging, or there is a higher demand for power than the alternator can put forward, it's going to produce peak current 100% of the time, and will wear those parts (bearings and contact brushes) to no tomorrow. I'm curious as to see you put an amperage clamp (inductive pickup) around the + wire from your alt to your battery, then from your battery to your fuse box and record the readings....sounds like a constant high amperage draw.

 

After I moved to Texas, I went through 2 alternators and 2 batteries in 2 years. Heat? Doesn't help. But after getting tired of replacing parts and having low voltage in stopped traffic (headlights on, both fans on, A/C), I decided to replace the battery cables.

Problem solved.

My old stock cables looked great. No corrosion on the terminals. No cuts showing any bare wiring along the cable. But with old age, the cables tend to build up resistance inside the cable where you can't see it. Our high humidity here probably doesn't help in that regard. Being in New Orleans, you have similar weather.

Went with the InnovativeWiring.com battery cables for our cars. Voltage is higher than it has been in years. Starts up easier. Brighter headlights. And I haven't had to replace a battery or an alternator since. The car with a 105 amp alternator works better with these cables than the stock cables did with a prior 140 amp Powermaster alternator.




I liked the results so much, that I bought their kit for our Blazer as well.