Californua resident where freezing is not an issue, I have always used distilled or deionized water in my cooling systems. Mainly because of cleanup disasters when losing a hose or water pump. Many race tracks ban antifreeze for this reason.

Also no environmental issues to deal with when changing coolant.

Have always added either a Prestone type anti-rust or a Water Wetter type product which includes anti corrosion substances.

I am aware of higher boiling point attributed to antifreeze mixtures,,,however with a 15 pound radiator cap, the addition of antifreeze offers marginal benefit. Perhaps 12 degrees.

One question I have always had was,,,must I continue to drain water and replenish occasionally,,,or can one just throw another can of anti-rust from time to time,,,within reason of course.

Some friends think I am nuts,,,,however my 71 Corvette is almost 50,,,original radiator and heater and coolant shows no rust.

I am now wondering if I should have same behavior on my aluminum headed Challenger. Runs a aluminum radiator with a 190 thermostat.

Opinions??

Anyone else doing this?