Principles of Operation

Engine Cooling

Special Tool(s):

Principles of Operation
The engine coolant flows from the lower radiator hose to the coolant pump. From the coolant pump, the coolant is then sent through the engine block and cylinder heads. The coolant pump is operated by engine rotation through a pulley which is driven by the accessory drive belt, circulating the coolant. The coolant thermostat controls coolant temperature and allows for quicker engine warm-up. When the thermostat is closed, the coolant returns to the coolant pump. When the thermostat is open, the coolant flows back to the radiator to transfer engine-generated heat to the outside air. The degas bottle serves many purposes which includes holding surplus coolant when hot and removing air from the cooling system, which reduces hot spots. It also allows coolant expansion and system pressurization, replenishes coolant to the cooling system and serves as the location for service fill. The cooling fan and shroud, when in operation, draws air through the radiator to help cool the system coolant as it passes through the radiator.