5442700TP Mercruiser STERNDRIVE, Bravo-III X (2.43:1 Ratio)

Illustration 1 g00390032
(1) Jacket water pump
(2) Tube
(3) Engine oil cooler
(4) Block
(5) Cylinder head
(6) Water manifold
(7) Aftercooler
(8) Regulator housing
(9) Tube
(10) Bypass tube
(11) Radiator or heat exchangerCoolant flows to jacket water pump (1) through an elbow that connects to the radiator or heat exchanger (11). Part of the coolant is sent to the aftercooler while most of the coolant is sent through engine oil cooler (3).Note: There is one opening on the pump outlet so that a remote pump can be connected to the system. The remote pump can be used if there is a failure of the pump on the engine.The coolant that is sent to the aftercooler goes through the aftercooler core. The coolant then goes through an elbow. The coolant goes into a passage in the block. The passage is near the center of the vee at the rear of the block. The coolant that is sent to the engine oil cooler goes through the engine oil cooler. The coolant flows into the water jacket of the block at the right rear cylinder. The cooler coolant is mixed with the hotter coolant. The mixture goes to both sides of the block through distribution manifolds. The distribution manifolds are connected to the water jacket of all the cylinders. The main distribution manifold is located just above the main bearing oil gallery.The coolant flows upward through the water jackets. The coolant flows around the cylinder liners from the bottom to the top. Near the top of the cylinder liners, the water jacket is made smaller. This is the area that has the hottest temperature. This smaller area causes the coolant to flow faster for better liner cooling. Coolant from the top of the liners flows into the cylinder head which sends the coolant around the parts that have the hottest temperature. Coolant flows to the top of the cylinder head (one at each cylinder). The coolant flows out of the cylinder head through an elbow into water manifold (6). Coolant then flows through the manifold to the temperature regulator housing (thermostat).Regulator housing (8) has an upper flow section and a lower flow section. The regulator housing uses four temperature regulators. The sensing bulbs of the four temperature regulators are in the coolant in the lower section of the housing. Before the regulators open, cold coolant is sent through the bypass line back to the inlet of the water pump. As the temperature of the coolant increases, the regulators start to open. When the regulators open, the coolant flow in the bypass line is then restricted. Coolant is sent through the outlets to the radiator or heat exchanger (11).Separate Circuit Aftercooling
Illustration 2 g06217699
(1) Cylinder block
(2) Engine oil cooler
(3) Regulator housing
(4) Jacket water pump
(5) Radiator
(6) Aftercooler
(7) Separate circuit water pumpCoolant flows to jacket water pump (4) through an elbow connected to a coolant tank in radiator (5). The coolant flow is sent through engine oil cooler (2).The coolant flows through the engine oil cooler. The coolant then flows into the water jacket of cylinder block (1) at the right rear cylinder. The coolant flows to both sides of the block through the distribution manifolds. The distribution manifolds are connected to the water jacket of all the cylinders. The main distribution manifold is located just above the main bearing oil gallery.The coolant flows upward through the cylinder water jackets and around the cylinder liners from the bottom to the top. Near the top of the cylinder liners, the water jacket is made smaller. This is the area that has the hottest temperature. This smaller area causes the coolant to flow faster for better liner cooling. Coolant from the top of the liners flows into the cylinder head which sends the coolant around the parts that have the hottest temperature. Coolant flows to the top of the cylinder head (one at each cylinder). The coolant flows out of the cylinder head through an elbow into a water manifold and then through the manifold to the temperature regulator housing (thermostat) (3).Regulator housing (3) has an upper flow section and a lower flow section. The regulator housing uses four temperature regulators. The sensing bulbs of the four temperature regulators are in the coolant in the lower section of the housing. Before the regulators open, cold coolant is sent through the bypass line back to the inlet of the jacket water pump (4). As the temperature of the coolant increases, the regulators start to open. When the regulators open, the coolant flow in the bypass line is restricted. Some of the coolant is sent through the outlet of radiator (5) for the jacket water system (5).Coolant flows to separate circuit water pump (7) through an elbow connected to a coolant tank in radiator (5). The coolant flow is sent through aftercooler (6).Coolant flows through aftercooler (6) and back to the coolant tank in radiator (5). The coolant is then sent through the outlet of radiator (5) for the separate circuit cooling system.