875433 Volvo.Penta Gear housing

Illustration 1 g02797136
(1) Radiator
(2) Water Pump
(3) Cooling Fan
(4) Water Temperature Regulator
(5) Cylinder Head
(6) Cylinder Block The cooling system cools the engine while the engine is running to prevent overheating and maintain a proper operating temperature.These engines are a pressurized forced-circulation type of cooling system.The coolant is cooled through the radiator core, and the fan (3) set behind the radiator (1) pulls cooling air through the core to improve cooling.When the coolant in the engine is at a low temperature, the water temperature regulator (4) valve is closed. The coolant is circulated in the engine through the bypass pipe. When the temperature of the coolant becomes the valve opening temperature of water temperature regulator, the water temperature regulator opens the valve to return the heated coolant to the radiator.The water pump sucks the cooled coolant, forces the coolant into the cylinder block, and draws out the hot coolant.Bottom Bypass System
These engines have a bottom bypass system to enhance the cooling performance.
Illustration 2 g02797158
Bypass Opened
(4) Water Temperature Regulator
Illustration 3 g02797159
Bypass Closed
(4) Water Temperature Regulator When the temperature of the coolant in the engine is low, the water temperature regulator (4) stays closed. When the regulator is closed, the coolant flows through the bypass pipe and around the engine.When the temperature is more than the water temperature regulator valve opening level, the water temperature regulator opens up fully. The hot coolant cannot flow through the bypass into the engine and can flow into the radiator. The radiator can decrease the temperature of the coolant more easily.Water Pump
Illustration 4 g02797166
(7) Bearing Assembly
(8) Water Pump Housing
(9) Mechanical Seal
(10) Impeller The water pump circulates the coolant through the system.If the pump fails to circulate the coolant, heat is not removed from the engine and overheating damage may occur.These engines use a centrifugal type water pump, and the pump driven by the crankshaft by a fan belt. The water pump is composed of a pump body (8), impeller (10), mechanical seal (9), and bearing assembly (7).Cooling Fan
Illustration 5 g02797182
(A) Suction Type Cooling Fan
(B) Blower Type Cooling Fan The cooling fan is located on the water pump shaft with a fan pulley, and is driven by a V-belt from the engine crankshaft.The cooling fan is made of steel or synthetic resin, and the blower capacity of the fan varies according to the number of blades, twisting angle, outside diameter, and rotating speed.Generally, large diameter cooling fan provides sufficient cooling air at low rotating speed. However, the same cooling effect can be obtained with a smaller diameter fan by providing higher fan speed or fan blades with a steep-blade angle. This design allows a more compact installation.The fan can be either a suction type or a blower type, depending upon the design of the system.Suction type cooling fan. This fan pulls air through the radiator and pushes the air over the engine. This design permits the use of a smaller fan and radiator than is required for blower type fan. The suction type cooling fan is used when machine motion aids air movement through the radiator.Blower type cooling fan. This fan pulls air across the engine, then pushes the air through the radiator. This type is used in slow-moving machine, and on machine where harmful materials might be drawn into the radiator with a suction type fan.