811379 Mercruiser FRONT FLANGE

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Coolant Flow ( Engine Without Jacket Water Aftercooler) (1) Radiator (2) Pressure cap (3) Inlet line to radiator (4) Water Temperature Regulator (5) Cylinder head (6) Cylinder block (7) Inlet line to water pump (8) Water pump (9) Internal bypass line (shunt line) (10) Engine oil filter (11) Engine oil cooler (12) Elbow (13) Cylinder linerWater pump (8) is located on the left front side of the engine and the water pump is gear-driven by the timing gears. Coolant from the bottom of radiator (1) flows to the water pump inlet. The impeller rotation in water pump (8) pushes the coolant through the system. All the coolant from water pump (8) travels through engine oil cooler (11). Elbow (12) on the outlet side of engine oil cooler (11) connects to the side of cylinder block (6) .On engines with a torque converter oil cooler, a bonnet is mounted on engine oil cooler (11). This bonnet diverts the coolant through the second cooler, before the bonnet allows the coolant to enter cylinder block (6) .The coolant enters the cylinder block. Then, the coolant flows around cylinder liners (13), through the coolant directors, and into cylinder head (5). The coolant directors force the coolant flow around the valves and around the exhaust ports (passages) in the cylinder head. The coolant now flows to the front of the cylinder head. At the front of the cylinder head, water temperature regulator (4) controls the direction of the coolant flow. If the coolant temperature is lower than the regular setting, the water temperature regulator (4) is closed. The coolant must pass through internal bypass (9) to the water pump. When the coolant reaches the regular temperature settings, water temperature regulator (4) opens. Most of the coolant flows through radiator inlet line (3) to the radiator, although some coolant still passes through internal bypass (9).
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Coolant Flow ( Engine With Jacket Water Aftercooler) (1) Radiator (2) Pressure cap (3) Inlet line to radiator (7) Inlet line to water pump (8) Water pump (9) Internal bypass line (shunt line) (11) Engine oil cooler (12) Jacket Water Aftercooler (13) Aftercooler inlet line (14) Return line from aftercooler (15) BonnetWater pump (8) is located on the left front side of the engine and the water pump is gear-driven by the timing gears. Coolant from the bottom of radiator (1) flows to the water pump inlet. The impeller rotation in water pump (8) pushes the coolant through the system. The coolant flow from the water pump (8) is divided. A portion of coolant flows through the engine oil cooler (11). Bonnet (15) connects to the side of the cylinder block.Engines with an auxiliary oil cooler use a different bonnet. This bonnet sends the coolant flow through the auxiliary cooler. The auxiliary oil coolant is for attachments.The coolant flows through one side into the auxiliary oil cooler. At the bottom of the auxiliary oil cooler, the flow turns. The flow turns back through the other side, and into the bonnet. The bonnet directs the coolant into the cylinder block.The remainder of the coolant flow goes through the aftercooler inlet line (13). The coolant then flows into the core of the aftercooler (12). The core of the aftercooler (12) is a group of plates and fins. The coolant flows through the plates. The inlet air for the engine flows around the fins. This cools the inlet air.The coolant comes out of the aftercooler (12) at the rear of the engine. The coolant then flows through return line (14) to bonnet (15). The coolant joins with the coolant from the engine oil cooler (11). The coolant then flows in bonnet (15) and flows into the cylinder block.Cooling System Components
Water Pump
The centrifugal type of water pump has two seals:
One prevents leakage of water.
One prevents leakage of lubricant.An opening in the bottom of the pump housing allows any leakage to escape. There may be coolant leaks around the water seal. There may be coolant leaks around the rear bearing seal.Fan
The fan is driven by two V-belts from a pulley on the crankshaft and by the fan drive. Belt tension is adjusted by the clamp assembly that includes the fan mounting and pulley.