Antifreeze has a shelf life, the general shelf life of 5 years, if there is deterioration will produce impurities, antifreeze will lose its original characteristics, impurities may also cause clogging, attention should be paid to timely replacement of new antifreeze. Antifreeze can prevent the coolant from freezing in the cold winter when parking and expanding the radiator and freeze the engine cylinder block, the full name of the antifreeze coolant. Antifreeze is a kind of coolant containing special additives, mainly used for liquid-cooled engine cooling system, with winter antifreeze, summer anti-boiling, year-round waterproof scale, corrosion and other excellent performance. Engine and its cooling system is made of metal, copper, iron, aluminum, steel and solder, these metals in contact with water at high temperatures, will be corroded and rusted for a long time, antifreeze not only does not cause corrosion of the engine cooling system, but also has the function of anticorrosion and rust.