I always do..
I used to built custom water cooled PC's for sales to games and still do from my own systems..
The rad and so on use the same metal and parts to a car in most cases and If found massive cooling differences in in % of water to coolant
The more the plain water the better and quicker the heat goes but you need to have enough coolant to stop corrosion and that's really its only job unless you live in sub 0c haha