Why is water used as a coolant in car radiators?
It is not water. It is a mixture of ethylene glycol (Anti-Freeze) and water. The ethylene glycol can not be used straight. It must be diluted to reach its optimum resistance to freezing. Straight ethylene glycol will freeze at about 20F. When mixed with the proper amount of water it won’t freeze until about -50F. Also, just because you live in a warm climate doesn’t mean that you should be using water only. The correct mixture of ethylene glycol will increase the boiling point of your coolant. One last thing. You should never use plain tap water. It has trace amounts of chemicals and minerals that can cause corrosion in your cooling system. You should dilute the ethylene glycol with distilled water.
Water is used in tropical countries and anti freeze is used in countries which have a winter with temperature reaching in the minus degrees to prevent the water pump from freezing during a cold start, Water is used because it does not exceed the temperature above 100 deg.C no matter how hot the engine is it will try to maintain the temp of the engine to 125 deg C. in the cylinder area. Using distilled water is advisable because all the calcium and impurities are removed which helps the seals and bearings from premature wear.
