The system functions as follows. When the engine is cold, the thermostat is closed, the water pump pumps water through the internal channels, through the bypass hose (and the heater circuit, if it is on) over the thermostat capsule and back to the water pump inlet.
The circulated water cools the engine cylinders, combustion chamber surfaces and valve seats. However, when the refrigerant reaches a certain temperature, the thermostat starts to open. The coolant now begins to circulate through the top hose to the top of the radiator. As it passes through the radiator, the fluid is cooled by airflow as the car moves, powered by an electric cooling fan if needed. Finally the coolant returns to the water pump through the bottom hose and open thermostat.
The electric cooling fan is controlled by a thermal switch located at the base of the radiator. The fluid temperature is monitored by a sensor in the cylinder head.
Note: The electric cooling fan starts working when the coolant temperature in the radiator reaches a certain level, even if the engine is not running. Therefore, be careful when working near the fan blades.
Visitor comments