1992 corvette

[danF]

Hello Gents,
1992 corvette put a new Napa Legend in it in June, I don’t drive the car much maybe 1k a year.
Drove it a little and it sat for a month and a half. Took it out last week and went for a ride no problems. When I got home and was inside for a while I noticed a small puddle under the battery compartment on the ground. I went out and removed the battery and it was leaking from the vents on both sides. I cleaned up the mess with some baking soda and water.
I was able to get a new battery under warranty, my friend who is a mechanic came over with a battery tester and volt meter, the battery was installed the charge said normal on the battery tester. We then put it on a volt meter it said 14.5 then went down to 14.2 to 14.3 after it warmed up for a while. The same reading my digital readout was giving me in the car. I then drove it for an hour came back and checked it on a voltage meter again it said 14.2 the same as the cars readout said.
Today when I checked the oil, I noticed acid was coming out of the vent, not as much as before, but it was starting to form in the tray, I removed the battery again.
Guys any ideas, I will replace the alternator, but it is charging at 14..2 when warmed up 14.6 cold start and 13.9 at night with lights on. I don’t believe I would get 2 bad batteries (new)
Thoughts,
Thanks,
Dan

 

[FTTSHO]

My 2001 blazer has the Napa legend battery. Group 75. The sticker says 3/21, battery is still going strong at over 4 years, but probably should still change it soon, because I do not like being stranded.

I’ve always had great luck with Napa batteries. Always got many many years out of them. But not sure if the quality is still as good as it was.

I would check your charging system first, especially the alternator. Then proceed with a new battery. You probably should just get a new battery to be safe, especially after it has foamed and leaked, which could just be a defect.

 

[dishdude]

Get one of those voltmeters that plug into the cigarette lighter and monitor it while driving.

 

[danF]

Get one of those voltmeters that plug into the cigarette lighter and monitor it while driving.

I put a voltmeter on it several times and it read the same as the reading on the car 14.2 which is suppose to be perfect, I’ll order a new ac delco alternator tomorrow, and I’ll send the old one to be rebuilt as it is the original that came with the car, it only has 50k miles on it, I’ve owned it for 30 yrs it is always garaged and never seen rain or sits in the sun

 

[dishdude]

I put a voltmeter on it several times and it read the same as the reading on the car 14.2 which is suppose to be perfect, I’ll order a new ac delco alternator tomorrow, and I’ll send the old one to be rebuilt as it is the original that came with the car, it only has 50k miles on it, I’ve owned it for 30 yrs it is always garaged and never seen rain or sits in the sun

It probably has a CS alternator which was just terrible, so replacement might not be a bad idea. II don't recall them being known to overcharge.

 

[Chris142]

You need to check the amperage not just the volts

 

[tblt44]

The volts look good but maybe as Chris142 said.
I would not know how to check amps myself without a google search

 

[meep]

I wonder if that 14.2 is an average but there could the AC voltage that is forcing the battery to overcharge. I’m not sure if setting the meter to AC voltage would give you anything useful thought. Alternator may be losing a diode.

 

[TomYoung]

You definitely need to chase this down. Nothing good comes from a battery that is boiling. There are many electrical diagnostics possible, but you might consider getting a rebuilt AC Delco alternator from Rockauto for $120. It has an internal voltage regulator, which is odds on the problem. I actually have done one of these in the past, and while alternator replacement is generally not the hardest job, in a ‘92 Vette, it’s child’s play. Good luck.