Illustration 35 Cooling System Schematic

TM 9-2320-312-24-2

Systems Operation Section

Cavitation is the sudden formation of low pressure

bubbles in liquids by mechanical forces. The

formation of air or steam pockets is more difficult

within a pressure type cooling system.

The shunt line prevents cavitation by the water

pump. The shunt line provides a constant flow of

coolant to the water pump.

Note: In air to air aftercooled systems, a coolant

mixture with a minimum of 30 percent ethylene

glycol base antifreeze must be used for efficient

water pump performance. This mixture keeps the

cavitation temperature range of the coolant high

enough for efficient performance.

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Illustration 36

Water Lines Group

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Illustration 35

(1) Cylinder head. (2) Water temperature regulator housing. (5)

Bypass hose. (9) Water pump. (10) Outlet to radiator. (11) Water

Cooling System Schematic

temperature regulator. (12) Air vent valve in thermostat.

(1) Cylinder head. (2) Water temperature regulator housing. (3)

Expansion tank. (4) Shunt line (expansion tank to water pump).

From the cylinder block, the coolant flows into

(5) Bypass hose. (6) Radiator. (7) Cylinder block. (8) Oil cooler.

passages in the cylinder head. The passages send

(9) Water pump.

the flow around the unit injector sleeves and the

Water pump (9) is located on the right side of the

inlet and the exhaust passages. The coolant now

cylinder block. The water pump is belt driven from

enters water temperature regulator housing (2) at

the crankshaft pulley. Coolant can enter the water

the front right side of the cylinder head.

pump in three places:

Water temperature regulator (11) controls the

the inlet at the bottom of the water pump

direction of flow. When the coolant temperature

is below the normal operating temperature,

the bypass hose (5) into the top of the water

the water temperature regulator is closed. The

pump

coolant is directed through bypass hose (5) and

into the top inlet of the water pump. When the

the shunt line (4) into the top of the water pump

coolant temperature reaches the normal operating

temperature, water temperature regulator (11)

Coolant from the bottom of the radiator is pulled into

opens. When the water temperature regulator is

the bottom inlet of the pump by impeller rotation.

open, the bypass is closed. Most of the coolant

The coolant exits the back of the pump directly into

goes through outlet (10) to the radiator for cooling.

the oil cooler cavity of the block.

The remainder flows through bypass hose (5) and

into the water pump.

All of the coolant passes through the core of

the oil cooler and the coolant enters the internal

Note: Some coolant systems may contain two water

water manifold of the cylinder block. The manifold

temperature regulators.

disperses the coolant to water jackets around the

cylinder walls.