very true we have had it happen on one of the racecars. it was a alloy radiator and it just got a big split in the side. wansnt earthed properly

Surely that was due to extended periods of corrosion, not one single moment?

Well, sounds like Mr Repco wasn't all wind. So how do you ensure that your vehicle is earthed properly then?

Run a system of heavy gauge wire in a network between grounding points to your car. You can buy ready made earthing kits for cars, but you can make your own easily enough. I have extra cable going from my strut tower to the engine and strut tower to alternator chassis. To check if you have a bad earth, check for voltage betwen earthing points - it should be under 0.2 volts or so (I forget the exact figure, but the lower the better) on maximum load (lights, fans on etc).

Example, probe the body of your car, and the engine block. If you get, say, 2-3 volts, you have a really bad earth lead, or one thats just not heavy enough in guage. You want the lowest resistance possible between earth points, so the larger the wire the better, and keep the contact points clean and use something like lanotec to protect the points after.

I fitted a new radiator from NATRAD as mine was corroded out on the outside.It cost me $270.00 supply only.