Have an 86 Iroc LB9 that threw a code 53 yesterday. At times the volt guage would go up to 18 volts. When I popped the hood battery water/acid was bubbling out. I took the alternator out of the car and tested it at Autozone and it passed the tests. I also refilled the battery back up with distilled water and had that tested and it was fine. So I hooked everything back up and cleared the code. It happened again today though. Any idea on what is causing the problem? Any help is appreciated. Im sure all that voltage is not a good thing.

 

 

I, too, would try a different alternator. These are internally regulated to make sure they are not putting out too much juice.

The one time I had a battery explode on me while driving, it was because my voltage regulator failed. I hope you got all that acid off of everything, as it's highly corrosive!

 

I went to Autozone since I have a lifetime warranty on the alternator and was able to get a new one. So we will find out tommorow. Yeah I cleaned all that acid up. I couldn't believe how much came out. There was even a little puddle on the ground under the battery tray Luckily the alternator didn't ruin the battery.

 

This may be a situation that the alternator is chrging the battery with ac voltage which I have seen before causing this problem.Yea sure the alternator is working but what kind of voltage is it charging?{bad diode}

 

Diodes only block voltage from backfeeding, almost like a check valve.

Diode

If the alternator is getting only AC voltage its a rectifier problem, still an internal issue in the alternator.

Rectifier

Replace the alternator

 

another possible scenario, the fusible link on the alternator feedback wire is blown. the red wire in the 2 wire harness, goes to the batt terminal of the starter. if the alternator gets no feedback, it pumps out max voltage to charge the battery it sees as being dead.