I don't care if someone uses uranium hexafluoride to cool an engine. If those pistons and block gets to 260 degrees you'd better find a good place to pull or start thumbing through the yellow pages for a scrap iron dealer paying the highest prices.
Coolant has a NASTY habit of pitting wet cylinder liners and other hot spots like around valve seats. Nalcool 2000 has been used for decades as an additive to try ans thwart erosion that puts pea-size holes into water jacket liner areas. In addition any company that sells safety pins to nuclear reactors that conveniently "forgets" to post clear and cognizant data that shows one of its MOST IMPORTANT RESPONSIBILITIES in this case BTU heat transfer ability in comparison to straight H2O and H2O Ethylene Glycol mix loses my interest instantly and forever.