Figure 2-20. Pressure flushing of radiator.

replaced and direct support notified for corrective cleaning.

(5) When vehicle is equipped with a heater or other

accessories such as overflow tank connected to the

cooling system, flush heater, following the same procedure

used for the radiator core.

(6) After completing flushing operation and before

connecting cooling system hose, clean all hose

connections of both radiator and engine block. Clean

radiator overflow pipe, inspect, and, if necessary, lubricate

water pump, clean thermostat, and radiator cap control

valves. Check thermostat for proper operation before

installation.

h. Leaks. Close the drain cocks. Pour water slowly

into radiator until the system is approximately half full.

Start engine, run at idling speed, and fill the system

completely. Stop engine and examine the entire cooling

system for leaks. Carefully check the radiator hose

connections, water pump mounting bolts, seal and gasket,

Figure 2-20. Pressure flushing of radiator.

thermostat mounting bolts and gasket, and cylinder-head

bolts and gasket. Inspect radiator core for leakage. This

(2) To flush engine block (fig. 2-21), proceed as

is important because the cleaning solution may uncover

follows:

leaks which existed but were plugged with rust or

(a) Remove thermostat and replace thermostat

corrosion.

Reconnect overflow tank if it has been

housing.

disconnected and inspect caps and gaskets to be sure that

(b) Clamp flushing gun nozzle firmly to hose

they are in good condition and fit securely.

attached securely to engine water outlet opening.

Coolant Service.

engine water inlet opening to facilitate complete filling.

(1) When servicing the engine for operation at

(d) Turn on compressed air to blow out water and

anticipated temperatures above 32F, nearly fill the system

loose sediment. Repeat filling with water and blowing out

with clean water Add COMPOUND, inhibitor, corrosion

with compressed air until flushing stream comes out clean

(FSN 6850-753-4967), in the proportion of one container

and then proceed as in f. above.

of inhibitor to each 4 gallons of cooling system capacity

including accessories. Then complete filling the system

(3) For most complete removal of sediment, repeat

with water. The capacity of the cooling system can be

flushing of radiator core and engine block in opposite

obtained from applicable technical manual.

direction.

(2) When servicing the engine for operation at

anticipated temperatures below 32F, use the procedure

prescribed for reclaimed or new antifreeze compound,

whichever is to be used. Inspect entire cooling system for

leaks and replace any hoses not suited for extended use.

2-22.

Special Instructions

a. One of the most common reasons for engine

damage due to overheating is operation with coolant level

low. Check coolant level daily before operation and add

coolant as required to bring level to top of filler neck If, at

any time, coolant loss exceeds 2 quarts, the system

should be thoroughly inspected for leaks (If no leakage is

found, radiator cap, or pressure relief valve if so equipped,

may be defec-

Figure 2-21. Pressure flushing of engine block.

(4) For badly clogged engine water jackets that do

not respond to regular pressure flushing, engine should be

2-17