3H6-07205-0 Tohatsu SEAT, VALVE SPRING

Illustration 1 g00306704
Jacket Water And Separate Circuit Cooling System (1) Coolant outlet to the heat exchanger (jacket water). (2 ) Water manifold. (3) Turbocharger coolant return tube. (4) Turbocharger. (5) Turbocharger coolant supply tube. (6) Engine oil coolers. (7) Elbow. (8) Aftercooler. (9) Right side water pump (jacket water). (10) Coolant inlet from the heat exchanger (jacket water). (11) Coolant supply to the engine oil coolers. (12) Coolant inlet from the heat exchanger (engine oil cooler and aftercooler circuit). (13) Water temperature regulator housing. (14) Left side water pump (engine oil cooler and aftercooler circuit). (15) Water connection group. (16) Coolant outlet to the heat exchanger (engine oil cooler and aftercooler circuit). (17) Coolant return from the engine oil coolers. (18) Coolant supply to the aftercooler. (19) 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 and 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.Water temperature regulator housings can be mounted in order to provide a controlled minimum pump inlet temperature (inlet controlled), or a minimum engine outlet temperature (outlet controlled).Separate Circuit Cooling System
In the separate circuit cooling system, the left side water pump (14) pulls coolant from the heat exchanger through inlet (12) . Coolant flow is divided at the water pump. Part of the coolant is sent to the engine oil coolers (6) while the rest of the coolant is sent to the aftercooler (8) . After the coolant flows through the aftercooler and the engine oil coolers, the coolant returns to the heat exchanger through coolant outlet (16) .There is a makeup line from the expansion tank to the coolant inlet (12) . This line helps keep the coolant in the circuit (engine oil cooler and aftercooler) at the correct level.A customer installed vent line is required between the top of the housing for the engine oil cooler and the expansion tank. This is for the circuit (aftercooler and engine oil cooler).Jacket Water Cooling System
The right side water pump (9) pulls coolant from the expansion tank through the coolant inlet (10) . Coolant from the right side water pump flows to the side of the cylinder block through elbow (7) .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