I have a 1990 toyota corolla. Last month, our alternator went bad, we fixed it. And then two weeks later, it was bad. We put in a new alternator, and it went bad a week later. We are on our 3rd alternator and are starting to see signs of it going bad again. Do you know what could be making our alternator go bad. Another thing I have noticed is our car idles really low. Could that have something to do with it. When we first start the car it is working alright, but then about 5 minutes into driving, you can see a change. I appreciate any advice you have. We spoke with a mechanic and he didn’t know what was wrong.
A bad battery can kill an alternator and vice versa. When I bought a rebuilt alternator last year for my 93 Chevrolet Caprice, the shop owner was very clear on this point.
How old is the battery? Has it been checked? A fully charged battery should be 12.6 to 12.7 volts. A discharged battery will read 11.9 Volts. A battery voltage of less than 10-11 Volts indicates a dead cell and the battery has to be replaced.
Thanks for the quick reply. I had the battery replaced last month. Any other ideas of what it could be?
A slow idle is definitely hard on the alternator…will not move enough air to keep the alternator cooled…
That doesn’t mean the battery is good. Have it analyzed to be sure. I had a truck that was eating alternators. You could easily tell the alternator was being overloaded. We checked everything electrical, and finally settled on the battery. It help 12V just find, and would start the truck. But on the analyzer, it read low enough on CCA to get a warranty replacement. That was the fix. The battery was causing too much amp draw on the alternator and killing it.