MKII Alternator is getting warm without running the Engine

[jts359]

I recently purchased a MK II with a Ford sm block which has a Ford alternator ,, I was doing some detailing the other day and noticed the alternator was warm to the touch and the engine had not been started ? I am going to do some trouble shooting later to day as I am pretty sure this is not normal ? The volt gauge reads about 13volts when its running , Any ideas ? , In the mean time I am turning off the main battery disconnect while the car is not running Thanks . Ed

[Jeff Kleiner]

The alternator has a failed diode or diodes. I'm betting that if it's a Mk2 you have a Mustang G2 alternator; if you replace it with the same ALWAYS replace the pigtail with the plug at the same time (they are often included with remanufactured alternators). Meanwhile, yes, keep the battery disconnect turned off.

Jeff

[PG_Cobra]

I had the same problem with mine a couple of decades ago. It turned out to be the regulator module in the alternator. Power is always applied to the alternator even with the ignition off. The regulator should shut off the stator coils when the ignition is off. A faulty module leaves them activated which means the alternator feels warm and the battery drains. Best of luck.

[jts359]

Thanks Guys I got a new alternator from my local Jobber and problem solved , Boy was the old one fugly . Ed

[steno]

Those gen 2’s have burned a number of cars and houses along with them!!!