The car water tank is called the radiator, which is the main part of the car cooling system.(2)

The car radiator doubles as water storage and heat dissipation. There is an air steam valve on the car radiator cover, and there is a public air hole that communicates with the atmosphere.

When the water temperature rises, the cooling water in the radiator of the car expands and the water vapor pressure rises, the steam valve is opened and vented; when the water temperature drops, the pressure drops, the air valve opens, and the outside air will flow from this common air hole. into the radiator to ensure stable pressure in the radiator.
During use, the public air holes should be kept unobstructed, and they cannot be blocked or lose their function, otherwise the heat dissipation performance of the radiator and the engine will be affected.

The cooling water in the radiator is not pure water, but a mixture of water, antifreeze and various special-purpose corrosion inhibitors, also known as coolant. The antifreeze content in these coolants accounts for 30%~50% , Improve the boiling point of the liquid, under a certain working pressure, the allowable working temperature of the car coolant can reach 120 degrees Celsius, which exceeds the boiling point of water and is not easy to evaporate.

The main job of the cooling system is to dissipate heat into the air to keep the engine from overheating, but the cooling system has other important roles as well.