There are good things and bad things that happen when you use only water with or without a wetting agent suchaas the above or by anyone else. First, if you are going to use only water, I would only use soft water to keep as many minerals out as possible, then use a rust inhibitor, or it will attack your aluminum as well as the cast iron. Why water works better is that it is able to draw more heat out of the base metal than a 50-50 blend of
antifreeze.
Antifreeze contains rust inhibitors and raises the boilin point of the coolant. Also if you live anywhere it will freeze you are risking busting a radiator or poping a soft plug on your block. Moorepower