The role of antifreeze:
1, antifreeze has the function of antifreeze, low freezing point. The freezing point of water is 0 ℃, the freezing point of antifreeze can reach -25 ~ -60 ℃. In the cold winter parking, to prevent the coolant from freezing and expanding the radiator and freeze the engine cylinder block, but also to ensure that the engine can be started at any time.
2, antifreeze has anti-boiling function, antifreeze boiling point is higher than water. Boiling point is the temperature at which the liquid boils. Under standard atmospheric pressure, the boiling point of water is 100 ℃, while the boiling point of antifreeze is higher than 106 ℃, can effectively prevent the engine "boil" phenomenon.
3, antifreeze has anti-corrosion function. As the engine cooling system, including steel, aluminum alloy, cast iron, copper and water tank welding with solder and other metals, cylinder block and cylinder head generally made of cast aluminum or cast iron, water tank is mainly made of copper and brass, antifreeze long-term contact with these metals, must be able to protect all of these metals, the use of deionized water and the appropriate additives to prevent the emergence of various types of corrosion
4, Antifreeze has "oily", can prevent non-metallic materials such as rubber, plastic dissolution, bulging, aging, etc., part of the vehicle antifreeze on the cooling system has a lubricating effect.
5, antifreeze can prevent the generation of scale. Scale is attached to the surface of the cooling system within the insoluble salts or oxide crystals. Produce scale of the main material is calcium sulfate, calcium carbonate, magnesium carbonate, etc., high-quality antifreeze using distilled water manufacturing, and add anti-scaling additives, not only does not generate scale also has the function of descaling.
Select antifreeze, usually should follow the following points:
1, according to the use of the unit's ambient temperature conditions to choose its freezing point (ie, freezing point). Freezing point is an important indicator of antifreeze, in general, its freezing point should be selected than the local environmental conditions of the lowest winter temperature lower than 10 ℃ or so appropriate; antifreeze grade is generally for its freezing point value, different areas of the purchase of the reference value should be different, south of the Yangtze River can be selected throughout the year for the grade of -25 antifreeze, some areas can also be selected for the freezing point value of the -15 ?C of the tank coolant; the Yangtze River to the north of the region, Northeast and Northwest should be used for -35 ~ -50 antifreeze. Note that different manufacturers, different grades of antifreeze can not be mixed.
2, according to the different requirements of the unit engine antifreeze selection, such as imported engines to choose a permanent antifreeze, while the domestic engine can be used directly to use the type of antifreeze, summer can be replaced by softened water.
3, as far as possible, the use of antirust, anticorrosion and antifreeze with the ability to remove scale. 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 over time, will rust. Antifreeze not only does not cause corrosion of the engine cooling system, but also has anti-corrosion and rust removal function.