The water pump forces the coolant to a passage in the front of the cylinder block. The coolant flows around the cylinders and into the cylinder head. Then, the coolant flows from the front of the cylinder head into the water temperature regulator housing.
When the engine is cold, the water temperature regulator is closed. Then, the coolant goes directly through a bypass to the inlet side of the water pump. When the engine warms, the water temperature regulator begins to open. Then, the regulator allows some of the coolant to flow to the top of the radiator. The regulator opens fully when the engine reaches the normal operating temperature. When the water temperature regulator is open, the bypass is closed and the coolant flows to the top of the radiator.
The water temperature regulator maintains the correct engine temperature by adjusting the direct flow of coolant to the top of the radiator. The coolant is cooled by the radiator. Heat is removed from the coolant by cooler air which passes over the radiator fins. The fan causes a high volume of air to flow between the radiator fins in order to provide sufficient cooling. The coolant flows from the radiator through the bottom hose to the coolant pump.
Different machine models have different locations for the radiator, the fan, and the fan drive. These three components may be remote to the engine. Then, the fan drive will be a hydraulic drive.