Bart: Thanks for your input, I just call him about your comments, he claims raicing cars use only water?? I wonder myself, since I heard this before. By the way, could you tell me if you use any special antifreeze coolant? or just the BMW ones? I could save money if I could use regular antifreeze. he's headed for some major cooling problems. Antifreeze contains lubricant and anti-corrosion agent. Without these the cooling system life is severely shortened, the water pump needs to be lubricated. It also raises the boiling point of water to keep your engine cool, a must especailly in hot weather.