Plain water only for racing, that glycol is extremely splipery. ethylene much cheaper than than Polypro. I've forgotten the specs, but polypro's used in solar and dry coolers etc the big AC systems (building etc). ethylene stands up to the engine enviroment much better.
This Dex-cool stuff suppose to have a property that idea for heat transfer in the head area. As usual I've forgot the word!
Paul
