[Aussie Mike]

I just had a chat with Norm at Aussie Desert Cooler about testing for stray voltage. Most auto manufacturers allow a maximum of 0.4V but once the car is out of waranty who cares. Norm recomends zero Volts. He says to test it, fill the cooling system with just clean water and then connecting a volt meter to chassis ground and the other probe to your radiator. Turn your ignition on, fire up the car and turn everything on and check the voltage.

If you are measuring stray volts turn things off one at a time and see what makes a difference. Norm says the problem is usually caused by bad earthing in the wiring loom.

Cheers