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| Illustration 1 | g01296123 |
Cooling System (1) Turbocharger (2) Water regulator (3) Inlet tube (radiator) (4) Aftercooler (5) Bypass (6) Water regulator housing (7) Water pump (8) Transmission oil cooler bonnet (9) Transmission oil cooler (10) Radiator cores (AA) Unregulated coolant (BB) Regulated coolant | |
Water pump (7) draws coolant directly from radiator (10). The coolant flows from pump (7) through the engine block. Coolant flows from the engine block to the transmission oil cooler bonnet (8). Coolant flows from the transmission oil cooler bonnet (8) to the transmission oil cooler (9). Coolant flows through the transmission oil cooler (9) and back to the transmission oil cooler bonnet (8). Then, the coolant flows through the engine block.
The coolant goes around the cylinder liners, through the water directors and into the cylinder head. The water directors send the flow of coolant around the valves and the passages for exhaust gases in the cylinder head. The coolant then goes to the front of the cylinder head and into water regulator housing (6). When the coolant is inside of housing (6), water temperature regulator (2) controls the direction of coolant flow within housing (6) .
When the coolant temperature is below 88.5° ± 1.5°C (190° ± 3°F), water temperature regulator (2) in water regulator housing (6) will be closed. The path for the coolant return to radiator (10) is blocked. The coolant flows through regulator housing (6). Then, the coolant is fed back to the inlet of water pump (7) .
As the coolant temperature reaches 88.5° ± 1.5°C (190° ± 3°F), water temperature regulator (2) starts to open. Coolant begins to flow to tube (3). When the coolant temperature reaches 98 °C (208 °F), the coolant is at normal operating temperature. Water temperature regulator (2) is fully open and the flow of coolant to bypass (5) is blocked. The path for the coolant to radiator (10) through the tube (3) is open. The temperature of the returned coolant will be reduced as the coolant flows through radiator (10).
Note: Water temperature regulator (2) is an important part of the cooling system. Water temperature regulator (2) divides the coolant flow between radiator (10) and bypass (5). Normal operating temperature is maintained. If the water temperature regulator is not installed in the system, the flow of coolant is not regulated. Most of the coolant will go through the bypass (5) and bypass radiator assembly (10). The engine, the transmission, and the hydraulic oil may overheat during high ambient temperatures.
Transmission Oil Cooler
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| Illustration 2 | g01296276 |
Schematic of Transmission Oil Cooler (9) (A) Coolant inlet port (B) Coolant outlet port (C) Oil outlet port (D) Oil inlet port | |
Coolant from the engine comes in at inlet port (A). The coolant flows through many long tubes that are in the cooler. After the coolant goes through the tubes to the end cover, the coolant is returned back through different tubes. The coolant then goes out through outlet port (B). Coolant from outlet port (B) returns to the engine cylinder block.
High temperature oil enters the cooler at outlet (D). This oil comes in at the side of the cooler. The oil flows around the tubes inside the cooler. In this process, heat is removed from the oil and transferred to the coolant of the engine. The coolant is then cooled by the engine cooling system.
After the oil flows around the tubes in the cooler, the oil flows through passage (C).
Coolant for the Turbocharger
Coolant for turbocharger (1) is supplied by a connection that is installed at the water pump (7). This port allows coolant flow through turbocharger (1). Turbocharger (1) has two inlets and two outlets. An inlet and a outlet are used for coolant flow. The coolant cools turbocharger (1) and flows back to radiator cores (10). The other inlet and the other outlet control the flow of oil that is used for lubrication of the bearings.
Radiator Assembly
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| Illustration 3 | g01296023 |
Radiator (Rear View) (4) Aftercooler (10) Radiator cores (11) Hydraulic Oil Cooler Core | |
Radiator assembly (10) is the source of coolant for the cooling system. The radiator is made up of the following three sections: radiator top tank, Radiator bottom tank and radiator core assemblies (10) .
Also, radiator assembly (10) includes air aftercooler (4), radiator core assemblies (10), and hydraulic oil cooler (11) .
The radiator top tank accepts the return coolant from the water regulator housing. The coolant flows from the radiator top tank down the tubes of radiator core (10). Then, the coolant flows into the bottom tank. As the coolant flows through the radiator core and the air is pulled around the radiator core, the temperature of the coolant is reduced.
Air to Air Aftercooler
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| Illustration 4 | g01295324 |
Air To Air Aftercooler (1) Turbocharger (4) Aftercooler (12) Air cleaner (13) Muffler (14) Cooled air enters the air intake manifold on right side of machine. (CC) Inlet Air (DD) Exhaust Gases | |
The air-to-air aftercooler system (ATAAC system) provides cooled air to air intake manifold (14) on the right side of the machine. Air is drawn in through air cleaner (12) and into turbocharger (1). The air is sent through the tube into aftercooler core (4). From core (4), the air flows into the air intake manifold (14) on the right side of the machine. The air flow from the inlet port into the cylinders is controlled by inlet valves. Each cylinder has inlet valves and exhaust valves in the cylinder head. The inlet valves open when the piston moves downward on the inlet stroke. When the inlet valves open, cooled compressed air from the inlet port within the inlet manifold is pulled into the cylinder. The inlet valves close when the piston begins to move up on the compression stroke. The air in the cylinder is compressed and the fuel is injected into the cylinder when the piston is near the top of the compression stroke. Combustion begins when the fuel mixes with the air. The force of combustion pushes the piston downward on the power stroke. The exhaust valves open and the exhaust gases are pushed through the exhaust port.
Exhaust gases from the exhaust manifold flow into the turbine side of the turbocharger (1). The high pressure exhaust gases cause the turbocharger turbine wheel to rotate. The turbine wheel is connected to the shaft that drives the compressor wheel. Exhaust gases from turbocharger (1) pass through the exhaust outlet, through a muffler (13), and through an exhaust stack.
The efficiency of the engine will increase due to the cooler inlet air. This helps to provide lowered fuel consumption and increased horsepower output. The air circulates through the intake manifold and flows back to turbocharger (1). From turbocharger (1), the air flows out of the system through muffler (13) .
ReferenceFor additional information about the turbocharger, refer to the Service Manual module Systems Operation, Testing and Adjusting, "Air Inlet and Exhaust System" for the engine that is being serviced.