Stray Current to Radiator Solved................................................

Willem why not earth the radiator to the engine? This will give an easier path for currents to flow.

Willem
There were a few good threads on this topic that also talked about coolants and copper radiators a while ago...it might be worth trying a copper radiator and coolant that will be compatable with cast, alloy and copper if you have a cast head.
My Toyota originally had alloy/plastic radiator and it was rubber mounted so no earth existed to chassis except through the block. Was your old rad rubber mounted too??
Andrew

What type of coolant alarm did you use Willem...I believe that the Redarc one uses AC current to avoid the problem you seem to have experienced.

Willem
I have one fitted to my Troopy, I have not had any problems , in fact if it wasn't there I'd done the motor twice , and one of those times was out across the Nullarbor.

.

It's true that the Low Coolant Alarm puts electrical current into the coolant. However this is such a low amount (45 micro amps @ 2 volts) that there is NO WAY it can cause electrolysis and damage any part of your engine. Mixing types of incompatable coolant is defo not a good idea.

Electrolysis can only occur if a current flows.

You can have two different metals in a conductive fluid - they might corrode slowly - but put the two diiferent metals in contact and they will corrode quickly.

When zinc anodes are put on a hull or outboard motor, they must be in electrical contact with the hull to be effective.

If your radiator is made of one metal, say aluminium, there will be minimal corrosion. There's iron in the engine block, but there's only one electrical path - the coolant. If you run a wire from radiator to engine block you are completing the electrical circuit and the aluminium and iron form a battery - whose current can flow through the wire.

I've checked the resistance from radiator fins to engine block on my 12 month old Pajero - 1500 ohms - what I'd expect for the coolant. The radiator is on rubber mounts.

The voltage measured is 0.1 volt or 100 millivolt. If I connect a wire from radiator to engine block, this voltage will drive rapid corrosion.

Thank you for all of your replies.

I realise now that the Low Water Alarm probably would not contribute to electrolysis within the coolant and that the real cause of the radiaotor failure must be incorrect coolant mix.


Cheers