955847 Volvo.Penta Hexagon nut

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Cooling system for a warm engine (typical example) (1) Cylinder head (2) Water temperature regulator (3) Vent lines (4) Outlet hose (radiator inlet line) (5) Vent line (6) Cylinder block (7) Shunt line (8) Turbocharger (9) Bypass tube (10) Power train oil cooler (11) Engine oil cooler (12) Jacket water pump (13) Radiator outlet (14) Radiator (15) Hydraulic demand fanThis engine is equipped with a pressure type cooling system that utilizes a shunt line. A pressure type cooling system gives two advantages. First, the cooling system can be operated safely at a temperature that is higher than the boiling point of water. Next, cavitation in the water pump is prevented. A pressurized cooling system prevents air or steam pockets from forming in the cooling system.Some engines are equipped with an Advanced Modular Cooling System (AMOCS) for heat dissipation. This radiator is constructed of several of the AMOCS cores that are modular in design. This design directs coolant flow from the bottom tank of the core to the top tank and back to the bottom again. This design maximizes the cooling effect of the radiator in a smaller space.ReferenceRefer to Operation and Maintenance Manual, "Caterpillar Machine Fluids Recommendations" for more information that relates to the coolant recommendations for your machine.During engine operation, jacket water pump (12) circulates most of the coolant from radiator (14) into engine oil cooler (11) . The coolant then flows from the engine oil cooler to power train oil cooler (10) . The oil coolers effectively transfer heat from the oil to the coolant. This helps to regulate the oil temperature in the engine and the power train.The coolant from the power train oil cooler flows into cylinder block (6) through a bonnet and an elbow. The coolant circulates throughout the water jacket area of the cylinder block. The coolant flows around the cylinder liners, through the coolant directors, and into cylinder head (1) .The coolant directors that are in the cylinder head send the flow of coolant around the valve passages and exhaust ports that are cast into the cylinder head. The coolant then flows to the front of the cylinder head. At this point, water temperature regulator (2) controls the direction of coolant flow.The water temperature regulator is closed when the engine is cold. The coolant flows through the regulator housing and bypass tube (9) back to the jacket water pump. Restricting the amount of flow that is directed through the radiator helps to warm the engine quickly.If the coolant is at normal operating temperature, the water temperature regulator opens and the coolant flows to the radiator through outlet hose (4) . As the coolant flows through the radiator, heat from the coolant is transferred to the air that is forced across the fins of the radiator. The air flow through the radiator is caused by hydraulic demand fan (if equipped) (15) . The hydraulic demand fan is a hydraulically driven fan. The fan is controlled by the Electronic Control Module (ECM) for the engine. The coolant exits the radiator through radiator outlet (13) and flows back to the jacket water pump.Note: The water temperature regulator is an important part of the cooling system. The water temperature regulator is used to divide the coolant flow between the radiator and the bypass tube. This maintains the engine at the correct temperature during all operating conditions. If the water temperature regulator is not installed in the system, there is no flow regulation of coolant through the radiator. This has the potential of causing an overheating condition or an overcooling condition during engine operation. Both conditions will shorten the life of the engine.Shunt line (7) gives several advantages to this type of cooling system. The shunt line gives a positive coolant pressure at the water pump inlet that prevents pump cavitation. A small flow of coolant constantly flows through the shunt line to the inlet of the jacket water pump. Vent lines (3) provide purge ports for the engine. Vent line (5) provides a purge port for the radiator. A continuous flow of coolant through the shunt line ensures that a small amount of coolant will continuously circulate through the vent lines. This circulation through the vent lines allows trapped air to be removed from the system while the engine is in operation. The vent lines also provide purging points from the system while the system is filled with coolant.Coolant for turbocharger (8) comes from a connection point that is at the water temperature regulator housing. This connection point allows coolant to circulate through the turbocharger only when the water temperature regulator is open. The coolant flows through a hose to the turbocharger cartridge. The coolant is used to cool the turbocharger cartridge.Coolant For Air Compressor
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Coolant flow in air compressor (typical example) (16) Inlet hose (17) Air compressor (18) Outlet hoseThe coolant for air compressor (17) comes from the cylinder block through inlet hose (16) . The coolant flows from the air compressor through outlet hose (18) and back into the front of the cylinder head.