Cooling System: Description and Operation
COMPONENTSThe cooling system has a radiator, coolant, electric fan motor, shroud, pressure cap, thermostat, coolant reserve system, transmission oil cooler, a water pump to circulate the coolant, hoses, and clamps to complete the circuit.
TWO THERMOSTAT OPERATIONS
When Engine Is Cold - Thermostat is closed, cooling system has no flow through the radiator. The coolant bypass flows through the engine only.
When Engine Is Warm - Thermostat is open, cooling system has bypass flow and coolant flow through radiator.
PURPOSE
Its primary purpose is to maintain engine temperature in a range that will provide satisfactory engine performance and emission levels under all expected driving conditions. It also provides hot water (coolant) for heater performance and cooling for automatic transmission oil. It does this by transferring heat from engine metal to coolant, moving this heated coolant to the radiator, and then transferring this heat to the ambient air. Coolant flow circuits are illustrated above.
COOLANT RECOVERY SYSTEM (CRS)
This system works with the radiator pressure cap to use thermal expansion and contraction of the coolant to keep the coolant free of trapped air. Provides a convenient and safe method for checking coolant 1evel and adjusting level at atmospheric pressure without removing the radiator pressure cap. It also provides some reserve coolant to cover deaeration and evaporation or boiling losses. All vehicles are equipped with this system and take various shapes and forms. The above image shows a typical system in the typical location. Vehicles equipped with the electric monitor system have a level sensor in the CRS tank.