The radiator doubles as water storage and heat dissipation, and an expansion tank is also installed on it. Because relying solely on the radiator has several disadvantages, one is that the suction side of the water pump is prone to boiling due to low pressure, and the impeller of the pump is prone to cavitation; the second is gas-water separation will cause vapor resistance; the third is that high-temperature coolant is prone to boiling. Therefore, the designer installed an expansion tank, and its upper and lower water pipes were connected to the upper part of the radiator and the water inlet of the water pump to prevent the above problems.