Chip,

basta ethylene glycol yung active ingredient ng coolant, it would automatically confer BOTH anti-freeze and anti-boil properties to the solution (would lower the freezing point and raise the boiling point), and it would probably have rust inhibitors as well. in other words, ethylene glycol aqueous solution is BOTH a coolant and an antifreeze

in other words, we still need antifreeze here in the tropics