What are the two water pipes above the car water tank for?

There are two water pipes in the car water tank. One end of the water inlet pipe is connected to the water chamber of the water tank, and the other end is connected to the water outlet of the water pump in the engine waterway. One end of the sewer pipe is connected to the sewer chamber of the water tank, and the other end is connected to the water inlet of the engine waterway. In this way, the cooling water circulation in and out of the engine and the water tank is formed.

The cooling liquid enters the reversing motor from the sewer pipe of the water tank through the water pump for cooling, and then comes out of the engine and enters the water tank through the water inlet pipe, and circulates in turn. We all know that when hot water goes up, the temperature above the radiator is high and the temperature below is low, which can also reduce the impact on the pump.