Alternator Problems



I received my parent’s 1991 Toyota Tercel in December with 67000 miles. In Feb I had the alternator and battery replaced when the car wouldn’t start. The rebuilt alternator failed in April. The third rebuilt alternator failed last week again. Is there something in the system that could cause this? Or have I just hit a streak of bad luck with alternators?


Yes you might have bad rebuilds. One of the problems with some rebuild mills is that they replace the failed component (usually a shorted or open diode) but just clean up the unit and put it back in a new box. A true rebuild should thoroughly check the stator windings for opens, shorts, and integrity of insulation, change the bearings, check and renew the rotor slip rings, put in new brushes, change all of the diodes, change the voltage regulator, and test the alternator for voltage and current output under hot conditions. Think of all the work that goes into the above and equate that with the cost of your rebuild to get an idea of how good a rebuild was done on your units.

You might have your latest failed alternator rebuilt by a auto electrical shop. They can determine what failed and surmise if there is something wrong with the battery/charging circuitry that caused the problem. When they install the rebuilt alternator, they can diagnosis the charging system to see if there are any problems. Alternately, you could have a OEM alternator installed. It will cost more but you will have the system back to where it was when the car was new.

On an aside, I had a neighbor who lost an alternator every year. They were all rebuilds but because he got a ‘lifetime replacement warranty’ with the first one the parts store kept replacing it – they weren’t too happy about it. I never got a chance to diagnosis the failure because he didn’t want anyone to fool with the unit so the store could deny replacement because of ‘tampering’. He traded the truck without ever finding out exactly why the alternators failed.

Let us know what you decide to do


I agree 100%, but you can also check the grounds on the body and engine, that they are clean and making good contact.


Bring it to Advance Auto and let them do their on-the-car electrical system diagnosis. That’ll give you an idea of what’s going on.

What kind of failure have the laternators been experiencing? Bearings? Diodes? Etc.