INSERT 4S8899 - Caterpillar

Illustration 1 g00309803
Cooling System With Separate Circuit Aftercooler Schematic
(1) Cylinder block. (2) Water cooled turbocharger (if equipped). (3) Engine oil cooler. (4) Regulator housing. (5) Jacket water pump. (6) Jacket water coolant source. (7) Aftercooler. (8) Thermostatic valve. (9) Separate circuit water pump. (10) Separate circuit coolant source
Coolant flows to the jacket water pump (5) through an elbow that connects to the jacket water coolant source (6). The coolant flow is sent through the engine oil cooler (3).The coolant flows through the engine oil cooler (3). The coolant then flows into the water jacket of the 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 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. 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. Coolant then flows through the manifold to the temperature regulator housing (thermostat) (4).Regulator housing (4) 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 (5). As the temperature of the coolant increases, the regulators start to open. The regulators restrict the flow of coolant in the bypass line. Some of the coolant is sent through the outlets to the jacket water coolant source (6).Coolant flows to the separate circuit water pump (9) through an elbow that connects to the separate circuit coolant source (10). The coolant flow is sent through the aftercooler (7).Coolant flows through aftercooler (7) and back to thermostatic valve (8). Before the thermostatic valve (8) opens, cold coolant is sent back to the separate circuit water pump (9). As the temperature of the coolant increases the thermostatic valve starts to open. The valve then restricts the coolant flow in the bypass line. Some of the coolant is sent through the outlet to the separate circuit coolant source (10).Coolant for the water cooled turbochargers (2) is picked up from the rear of the water manifolds. The coolant flows through the water cooled turbochargers (2) and the coolant returns to the regulator housing (4).