Coolant For Air Compressor (If Equipped)

TM 9-2320-312-24-2

Systems Operation Section

The shunt line (4) extends from the top of the water

If the engine is equipped with an air compressor,

pump to an expansion tank. The shunt line must

coolant is supplied from the water temperature

be routed properly in order to avoid trapping any

regulator housing to air compressor (3) through

air. By providing a constant flow of coolant to the

coolant supply line (1). The coolant is circulated

water pump, the shunt line keeps the water pump

through the air compressor and the coolant is

from cavitation.

returned to the cooling system through coolant

return line (2) into the cylinder head.

Note: Water temperature regulator (11) is an

important part of the cooling system. The water

Coolant Conditioner (If Equipped)

temperature regulator divides coolant flow between

the radiator and the bypass in order to maintain

Some conditions of operation can cause pitting.

the normal operating temperature. If the water

This pitting is caused by corrosion or by cavitation

temperature regulator is not installed in the system,

erosion. A corrosion inhibitor is a chemical that

there is no mechanical control, and most of the

provides a reduction in pitting. The addition of a

coolant will travel the path of least resistance

corrosion inhibitor can keep this type of damage

through the bypass. This will cause the engine to

to a minimum.

overheat in hot weather and the engine will not

reach normal operating temperature in cold weather.

The coolant conditioner element is a spin-on

element that is similar to the fuel filter and to the

Note: Air vent valve (12) will allow the air to escape

oil filter elements. The coolant conditioner element

past the water temperature regulator from the

attaches to the coolant conditioner base that is

cooling system while the radiator is being filled.

mounted on the front of the engine. Coolant flows

During normal operation, the air vent valve will be

from the water pump to the coolant conditioner base

closed in order to prevent coolant flow past the

and back to the cylinder block. Coolant constantly

water temperature regulator.

flows through the coolant conditioner element when

the valves are in the OPEN position.

Coolant For Air Compressor (If

The element has a specific amount of inhibitor

Equipped)

for acceptable cooling system protection. As the

coolant flows through the element, the corrosion

inhibitor goes into the solution. The corrosion

inhibitor is a dry solution, so the inhibitor dissolves.

The corrosion inhibitor then mixes to the correct

concentration. Two basic types of elements are

used for the cooling system. The two elements

are the precharge elements and the maintenance

elements. Each type of element has a specific

use. The elements must be used correctly in order

to get the necessary concentration for cooling

system protection. The elements also contain a

filter. The elements should remain in the system so

that coolant will flow through after the conditioner

material is dissolved.

The precharge element contains more than the

normal amount of inhibitor. The precharge element

is used when a system is first filled with new

coolant. This element must add enough inhibitor in

order to bring the complete cooling system up to

the correct concentration.

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Illustration 37

Coolant Lines For Air Compressor

(1) Coolant supply line. (2) Coolant return line. (3) Air compressor.