821440 1 Mercury EXHAUST TUBE

Illustration 1 g01344680
Separate circuit cooling system
(1) Oil temperature regulator
(2) Oil flow
(3) Turbocharger
(4) Cylinder block and cylinder head
(5) Oil coolers
(6) Mixer housing
(7) Inlet air
(8) Aftercooler
(9) Right side water pump
(10) Left side water pump
(11) Makeup line
(12) Orifice
(13) Water temperature regulator housing
(14) Expansion tank
(15) Water temperature regulator housing
(16) Heat exchanger or radiator
(17) Heat exchanger or radiator
Illustration 2 g01344686
Separate circuit and jacket water cooling system
(18) Coolant outlet to the heat exchanger
(19) Water manifold
(20) Turbocharger coolant return tube
(21) Turbocharger
(22) Coolant supply line for the turbocharger
(23) Engine oil coolers
(24) Elbow
(25) Aftercooler
(26) Right side water pump
(27) Coolant inlet from the heat exchanger
(28) Coolant supply to the engine coolers
(29) Coolant inlet from the heat exchanger
(30) Water temperature regulator housing
(31) Left side water pump
(32) Emergency water connection
(33) Coolant outlet to the heat exchanger
(34) Coolant return from the engine oil coolers
(35) Coolant supply to the aftercooler
(36) Coolant return from the aftercooler These engines use a separate circuit cooling system. The jacket water system (cylinder block, cylinder heads and turbocharger) is on one circuit. The aftercooler and the engine oil cooler are on a separate circuit. Water pumps are mounted on the front housing. The water pumps are driven by the front gear train. Coolant for the jacket water circuit is supplied by the right hand water pump. Coolant for the circuit with the aftercooler and the engine oil cooler is supplied by the left hand water pump. Water temperature regulators are used in each circuit in order to maintain correct operating temperatures.Oil Cooler And Aftercooler Circuit
In the separate circuit cooling system (oil cooler and aftercooler circuit), the left side water pump (31) pulls coolant from the heat exchanger through the inlet (29). Coolant flow is divided at the water pump. Part of the coolant is sent to the engine oil coolers (23) while the rest of the coolant is sent to the aftercooler (25). After the coolant flows through the aftercooler and the engine oil coolers, the coolant returns to the heat exchanger through coolant outlet (33).There is a makeup line from the expansion tank to the coolant inlet (29). This line helps keep the coolant in the circuit (engine oil cooler and aftercooler) at the correct level.A vent line is required between the top of the engine oil cooler's housing and the expansion tank. The vent line is installed by the customer. This is for the circuit (aftercooler and engine oil cooler).Jacket Water Cooling Circuit
The right side water pump (26) pulls coolant from the expansion tank through the coolant inlet (27). Coolant from the right side water pump flows to the side of the cylinder block through elbow (24).The coolant flows upward through the cylinder water jacket. 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 shelf (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. The 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 the water manifold (19). The coolant then flows through the manifold to the coolant outlet (18). The coolant exits the outlet and flows through a remote mounted water temperature regulator and the heat exchanger. The coolant then flows back to the expansion tank.Coolant is sent from the water jacket at the rear of the cylinder block through turbocharger coolant supply tube (22) to the turbocharger (21). Coolant from the turbocharger is returned to the cylinder block through turbocharger coolant return tube (20). A vent line is required between the top of the turbocharger and the expansion tank. The vent line is installed by the customer. This is for the jacket water system.