Deejay, just about all modern cars use 30 to 50 percent ethylene glycol (remainder water and minor additives) as their coolant, mainly for its antifreeze properties. Way back when I was a kid popular folklore said when you were stuck in a desert with nothing to drink, you could take the dirty water out of the car's radiator. That has been a really awful idea since at least the 1960s, when manufacturers started adding first corrosion inhibitor, and later glycol, to the water to lubricate the fuel pump and prevent rust. Automotive coolants are very poisonous - dying of thirst is a better way to go (and if you get lucky and someone finds you, you may even survive undamaged).
The minimum percentage of glycol that will prevent corrosion is about 30. Higher percentages are used mainly to give better antifreeze capability (lower the freezing point of the coolant), but also partly because adding glycol raises the boiling point of water and thus increases cooling system capability a bit.
Sparker, ethanol is good for drinking, at least if it is clean and diluted with water and flavouring agents, but it makes a rather poor engine cleaning agent and an even worse additive to petrol.
