Temperature difference between two water pipes in the heater box

Hello, let me tell you one of the simplest inspection methods, that is, the fan rotates and then stops. How about you feel the temperature difference between the upper and lower pipes again? Thermostat, as its name implies, is a device for adjusting temperature, which can also be said to be a "device for saving temperature". When the water temperature is lower than 83℃ (87℃ for some models), the thermostat is closed and the cooling system is in small circulation. Hot antifreeze is first provided to a warm air tank for heating. If the water temperature is always lower than the specified temperature when the thermostat is turned on, the cooling system will not circulate on a large scale. The function of thermostat is to control the engine coolant temperature at about 90℃, which is the best working temperature of the engine. I hope my answer is helpful to you.