The use of car anti-freeze had been decreasing recently, either as a result of modifications in engine or reduced extreme cold temperatures that usually occur during winter. Despite that, there are still places round the globe that it must be necessary to use anti-freeze during. The reason why such place must need it, is to avoid a total knock down of their car engine.
Even though a car is kept in a heated garage in winter, its cooling system may freeze up when the car is used. The first sign of a frozen engine will be the squeal made by the fan belt trying to turn the frozen water pump. If the car is driven straight from its heated garage when the air temperature is below freezing point, the thermostat will stay shut and the water in the radiator will not circulate. In a short time, soft, mushy ice will form in the radiator tubes, and they will become blocked.
Once this happens, even though the thermostat opens, no additional radiator cooling is available and the engine overheats. This is the reason why so many cars without anti-freeze are seen boiling on a freezing morning.
A good quality anti-freeze will prevent the cooling system from freezing. The higher the concentration of anti-freeze, the greater the protection. In Britain a 33% anti-freeze/water mixture gives adequate protection. In addition, it contains inhibitors which discourage rusting or corrosion, particularly of aluminum components, and so gives benefits all year round. Over a period (some anti-freezes have a claimed life of 2 or 3 years), the inhibitors lose their effect, and after the recommended lifetime the cooling system should be drained and the anti-freeze renewed. Note that, topping the anti-freeze with water alone can weaken the mixture in the anti-freeze.