I sent pictures of my latest find to a friend who happens to own a machine shop, he builds engines and has a very exstensive data base (in his head) with regard to anything automotive.He has a tip on averting electolysis in the radiator core. This is what he said to do. Go to any hardware store and buy a temperature pressure valve for a hot water heater (cheapest is good). Remove the zinc anode and cut off a 3" strip. Drill and tap one end for appropriate screw. Solder eyes on either end of a length of solid core (copper) wire. Attach one end of wire to the zinc anode, place it in the radiator overflow and attach other end to a suitable ground, like the frame. This allows the electrolysis to take place in the overflow rather than the radiator. Zinc anode requires replacement about once a year. <img src="/forums/images/graemlins/kewl.gif" alt="" />

Isn't easier to just use distilled water and change
the anti-freeze every two years and flush the radiator at
the change?

None of my vehicles have ever had any problems with corrosion,
but they are serviced like they should be.

The only Isuzu rad I have ever changed failed at the epoxy between the tubes and end tanks, and the little "fins" corroded and fell out. The tubes were in decent shape.