Hey guys. I bought a 1990 5.0L Mustang LX recently and it seemed to have no problems at all. But recently, the battery will not hold a charge for longer than 18 hours. I replaced the battery and the alternator, but still the battery will not keep its charge. I put my charger on it to charge at 2 Amps and the liquid in the battery is boiling out and smoking as well. Just wondering if anyone has any advice as to what it could be ? I'm thinking a short in the system and/or a voltage regulator ? Thanks in advance.

 

Does the car have an aftermarket sound system or a big amp?

Did you replace the alternator with a reman. or new one? (just because its new doesn't mean its good) have it checked.

When you charged the battery with the 2 amps, were the cables from the car connected?

What is the general condition of the wiring in the car, does it look like someone has done a bunch of "Mickey Mouse" wiring?

Does the starter "drag" or turn slowly while trying to start?

With the car running, what is the voltage at the battery terminals?

 

No aftermarket sound system, just an aftermarket Alpine deck from the mid 90's.

The alternator is a remanufactured one.

Yes the cables from the car were connected when I charged the battery.

The wiring looks pretty solid. Other then the wiring to the back of the stereo deck. Which looks pretty questionable.

Yes, but only when my battery is low. (70% of the time.)

I can't tell you the voltage cause I'm at work right now, ill check when I get home though.

 

Did you get a chance to check the voltage?

 

No I havnt, all of the fluid has boiled out of the battery. Now I need a new battery.

 

When you take the battery back also take the alternator back and have them check it for any problems. I believe that your car has a internal voltage regulator, make sure that all of this working. It should charge at about 13.3 to 13.8 volts, you may see 14 volts but not for a long period of time. Anything over 14 volts is overcharging and will boil your battery. Good Luck!

 

I havnt had a chance to get a new battery yet, but I remember when I drove the car, it was charging at 11 or 12 volts and the battery was still boiling.