22414309 Volvo.Penta Sensor

Illustration 1 g02022553
Coolant flow (jacket water)
(1) Pressure relief cap
(2) Top radiator hose
(3) Coolant inlet line
(4) Vent line
(5) Water temperature regulator
(6) Water cooled exhaust manifold
(7) Coolant outlet line
(8) Cylinder head
(9) Radiator
(10) Cylinder block
(11) Internal bypass
(12) Cylinder liner
(13) Bottom radiator hose
(14) Water pump
(15) Engine oil cooler
(16) Engine oil cooler bonnet Water pump (14) is located on the left front side of the engine. The water pump is gear-driven by the front gear train. Coolant from the bottom tank of radiator (9) is drawn through bottom radiator hose (13) by the water pump. The rotation of the impeller in the water pump pushes the coolant through the system.A portion of the coolant from the water pump goes through coolant inlet line (3) to water cooled exhaust manifold (6). The remainder of the coolant goes through engine oil cooler (15) to bonnet (16) on the outlet side of the engine oil cooler. Coolant flows through the bonnet into cylinder block (10).The coolant inlet line directs the coolant from the water pump to the front of the water cooled exhaust manifold. The coolant flows through the manifold to the rear of the engine. The coolant flows through coolant outlet line (7) into the oil cooler bonnet. The coolant is mixed with the remainder of the coolant.
Trapped air will cause hot spots in the water cooled exhaust manifold and in the cylinder head. Trapped air in the cooling system will cause high cooling system temperatures. Ensure that the vent line (4) is connected to the water cooled exhaust manifold and to some higher point in the cooling system. The vent line will prevent trapped air in the cooling system.
The coolant inside the cylinder block flows around cylinder liners (12). The coolant is pumped up through water directors into cylinder head (8). The coolant flows through passages around the valves and the combustion chambers that are in the cylinder head. The coolant flows into the front of the cylinder head to water temperature regulator (5). The water temperature regulator controls the volume and the direction of the coolant flow.If the coolant temperature is less than normal operating temperature, the water temperature regulator is closed. The only path that can be used by the coolant to exit the cylinder head is through internal bypass (11). The coolant from this line returns to the water pump. The water pump cycles the coolant through the system again. The flow of coolant through the bypass prevents cavitation by the coolant while the engine is warming up.When the coolant achieves normal operating temperature, the water temperature regulator opens and coolant flow is divided. The major portion of the coolant is sent to the radiator through top radiator hose (2). The remainder of the coolant goes through the internal bypass to the water pump.Note: The water temperature regulator is necessary to maintain the correct engine temperature. If the water temperature regulator is not installed in the system, control of the engine temperature is lost. The coolant will take the path of least resistance through the internal bypass. Bypassing too much coolant will cause the engine to overheat during periods of high ambient air temperature. During cold weather, the engine will not be able to achieve normal operating temperatures.While the cooling system is being filled with coolant, the internal bypass serves as a path for entrapped air. The internal bypass also allows the coolant to enter the cylinder head and the cylinder block without going through the water pump.Pressure relief cap (1) maintains a nominal pressure in the cooling system during engine operation. The pressure relief cap also allows makeup coolant from the expansion tank (if equipped) to enter the system as the engine cools. Engines that have a turbocharger have two cooling circuits. One circuit is for the engine jacket water that cools the engine and all of the attachments. The other circuit is a separate cooling circuit for the aftercooler. This cooling circuit is used for cooling the air in the aftercooler. This type of cooling system keeps the temperatures of the coolant in the two circuits in the correct range for the maximum horsepower output.The aftercooler circuit uses an auxiliary water pump. The auxiliary water pump is located on the left front side of the engine. The auxiliary water pump is gear-driven by the front gear train.
Illustration 2 g02022744
Coolant flow (separate circuit aftercooler)
(17) Aftercooler
(18) Aftercooler outlet line
(19) Aftercooler inlet line
(20) Water pump for the separate circuit cooling system The separate circuit cooling system utilizes a radiator core that is used to transfer heat from the inlet air for the engine to the coolant. For this application, the heat from the coolant is cooled by an external heat exchanger. The coolant for the system is pumped from the heat exchanger by water pump (20) through aftercooler inlet line (19) into aftercooler (17). The coolant goes through the plates of the aftercooler. The inlet air flows around the fins of the aftercooler. The heat is transferred from the air to the coolant. The coolant exits through aftercooler outlet line (18) to the heat exchanger for the system.