Auto radiator belongs to auto cooling system. In order to ensure the cooling effect, auto cooling system usually consists of auto radiator, thermostat, waterways on cylinder head, block waterways, water pump as well as fan and other parts. Cooling liquid is flowing within the core of auto radiator, while the air is passing through outside the core of auto radiator. The hot cooling liquid will cool down, for it distributes the heat to air, while the cooling air will raise the temperature, for it absorbs the heat released by cooling liquid. Therefore, auto radiator is a heat exchanger.

There are mainly two kinds of auto radiators, namely, aluminum-made auto radiator and steel-made auto radiator. The former is applied in the common passenger cars, while the latter is used in large commercial cars. Aluminum-made radiator has obviously advantage in the aspect of lightweight materials. Meanwhile, when aluminum-made radiators used in cars and lightweight cars are gradually replacing steel-made radiators, the production technology and working process of steel-made radiator have greatly developed. Copper brazing radiators are very excellent in the engine radiators of buses, construction machinery, heavy trucks and others. Most of auto radiators in foreign cars are aluminum-made radiators, for the sake of protecting environment.

Auto radiator is responsible for the cooling of cycled water. Its water pipe and cooling sinks are made of aluminum materials, while the aluminum-made water pipe is made into flat form, cooling sinks are the corrugated ones, which emphasize the cooling feature. In addition to cooling role, auto radiator can be also used to store water. Moreover, one air steam valve is installed on the head of auto radiator, and one public vent is connected with the air. When water temperature is rising, cooling liquid within the auto radiator would swell, the pressure of steam would increase, and thus the steam valve is opened and released. When water temperature is decreased, pressure is lowered, steam valve is opened, the outside air will enter auto radiator through this public vent, so that it can ensure that the inner pressure is stable inside the auto radiator. When auto radiator is used, people have to ensure the unblocked case in public vent, there is no block case or function loss, otherwise, it will impact the cooling feature of radiator and engine.

The cooling liquid in the auto radiator is not pure water, instead, it is a mixer which is formed by water, antifreeze and varied kinds of specific preservatives, it is also called cooling liquid. The content of antifreeze in cooling liquid accounts for 30% to 50%, and it enhances the boiling point of liquid. Under the certain working pressure, the allowable working temperature of auto cooling liquid can reach 120℃, which has exceeded the boiling point of water, so it is not easy to evaporate.