Can I use water instead of engine coolant to fill my car's radiator?
If you have a leaky radiator and your car is in danger of overheating, water will do. But if you are not in an emergency situation, it is best to stick to coolant. A good engine coolant prevents corrosion, facilitates better heat transfer than water, resists freezing (although not applicable in Singapore), resists scaling and clogging, remains stable at high temperatures, does not foam easily and is compatible with plastics and materials used in the engine.
AUTOMOBILE ASSOCIATION OF SINGAPORE