1989 charging system problem

[Tim Nicholson]

Hi, I have a problem with the charging system on my 89SHO. The battery appears to be over charging (boiling) causing battery acid to leak down on the battery bracket, etc. I replaced the alternator but it still looks like I am getting some leakage. Question is the voltage regulator, is it in the alternator or is it external? The Ford service manual isn't real clear for the SHO. Voltage at the battery while engine is running is <14.5V. If the regulator is external where is it? Rock Auto shows a listing for a regulator for the 89? Thanks in advance

 

[rbruso]

The regulator is internal, so you're looking at an alternator.

I have an Autozone with lifetime warranty. It lasted about 8 years, then was replaced under the warranty earlier this year.

Some people have had really bad luck with alternators, though. If you search, you'll find some nightmare threads about 2-3 replacement alternators in under a year.

 

[TYSHO]

How about changing the battery...

 

[TYSHO]

Voltage at the battery while engine is running is <14.5V

I'd be worried if it was >14.5, that's an indication of overcharging.

 

[shobote]

dangerous situation with that battery so better replace it quickly. the fumes are highly explosive so a key on situation can make it blow up. I had one explode once when I turned the key on and it sounded like a bomb going off.

 

[itwonder]

If the voltage at the battery is under 14.5 V when the motor is running (try revving it too), then the problem is less likely to be the voltage regulator than the battery. The battery may be developing a shorted cell, which would explain the issues you are having. I would try swapping batteries, or get a new one. You could have the battery tested , but those machines at AZ and the like are not as reliable as they should be. It's some trouble, but you could remove the alternator and have it tested. Also make sure no connections at the battery, grounds, or alternator are corroded.

The 90 amp alternator on the 89-93 SHO is not a ***** Ford product; it is Japanese made and an excellent piece. Don't exchange it away until you are certain it is broken.

 

[Phoenix]

Leaking batt = change it , has nothing to do with your charging system.

If you are getting 14-14,7 V engine on with idle or high rev , everything is normal.

If the batt light is on though , you have an issue with the alt.

 

[TYSHO]

You could have the battery tested

LOL... blow up the AutoZone worker. I'd pay someone to come remove that battery if it was mine, I had one blow up just like shobote mentioned. I started closing the hood with about 6 inches left and at that time my uncle turned the key and BOOM. I was gone like Forrest Gump.

I replace my batteries with any sign of corrosion. My life is worth $80. I don't play around with batteries. I had acid on my glove that was putting the hood down, and acid everywhere in the engine bay. It's not a game.

 

[Tim Nicholson]

Thanks to all that replyed to this post, it was a bad battery. The Wal Mart Tech tested it and it was putting out only 1/2 the cranking amps. The battery was still under warranty so free replacement. All I had to do was clean and repaint the battery tray etc, for the second time.