The basic function is to drive the coolant to dissipate heat from the engine. In the cylinder block of the car engine, there is a water channel for circulating cooling water, which is connected to the radiator (commonly known as the water tank) placed at the front of the car through a water pipe, forming a large water circulation system. At the upper outlet of the engine, there is a water pump, which is driven by a fan belt to pump out the hot water in the water channel of the engine cylinder block and pump in the cold water. There is also a thermostat next to the water pump. When the car is just started (cold car), it is not turned on, so that the cooling water does not pass through the water tank, but only circulates inside the engine (commonly known as a small circulation). When the engine temperature reaches 80 degrees or above, it is turned on, and the hot water in the engine is pumped into the water tank. The cold air blowing through the water tank when the car is moving forward takes away heat. This is roughly how it works.