Cleaning Compound

ing difficulties later.

Prompt attention to preventive

in amounts specified on cleaning compound container.

cleaning is the only sure way to avoid loss of equipment

Allow engine to continue running for 30 to 60 minutes.

use and extra work, time, tools, and materials required for

corrective cleaning of a rust-clogged system. Effective

(6) Stop engine and turn radiator cap to release

and safe preventive cleaning requires that only approved

pressure. As temperature rise can be expected at shut-

cleaning compounds be used, and that all service

down, coolant temperature should be allowed to drop

considerably below 200 F before draining and refilling with

operation specified in current directives be performed.

cold water to avoid cracking block and head, then remove

b. Cleaning Compound. The prescribed cleaning

the radiator cap and drain the system completely.

compound consists of the cleaner and neutralizer

compounds packed in separate containers within a single

CAUTION

package (para 2-22 (7)).

Do not hold air or water hose too close to radiator,

or use excessive pressure as damage to the

WARNING

radiator core may result.

Do not under any circumstances mix cleaning

compound with antifreeze compound or corrosion

e. Normal Flushing

inhibitor compound. Never mix the water and

(1) With engine stopped and temperature of coolant

considerably below 200F, open all drain cocks and

cleaning compound before putting it into the

cooling system. Do not spill compound on skin,

remove engine block drain.

clothing, or painted portions of vehicle. If spilled,

flush with clean water immediately.

(2) Add clean water and, while so doing, start the

engine at fast idle (drains open) Flush, continually flooding

c. Engine Temperature During engine idling periods

cooling system with clean water, engine running for 25

required in cooling system cleaning processes, it is

minutes.

important to cover the radiator and keep the cover

adjusted so that a temperature of 180 to 200F is

(3) Stop engine, close all pet cocks, install engine

maintained. The engine develops so little heat while

block drain, refill with clean water, maintaining level in

running without load that the thermostat valve remains

cooling system.

partially or fully closed. Covering the radiator opens the

valve quickly, but if the cover is removed, the valve will

NOTE

close again, even though the temperature gage shows

If antifreeze compound is to be added after

little change. With flow to the radiator restricted by the

flushing the radiator, do not add Inhibitor, discard

thermostat valve, cleaning, inhibiting, and flushing are not

it.

effective.

Inhibiting. Add inhibitor in amounts specified on

WARNING

cleaning compound containers to filled radiator, start and

run engine at idle until temperature reaches over 180F,

Remove radiator cap(s) slowly to relieve pressure

and avoid injury to personnel.

but not above 200F.

d. Cleaning.

g. Pressure Flushing

(1) Drain system by opening drain cocks. Make

(1) To flush radiator (fig 2-20), proceed as follows:

certain temperature of coolant has dropped considerably

(a) Remove both upper and lower hoses connecting

below 200 F before draining and refilling with cold water

the radiator to engine block.

to avoid cracking block and head.

(b) Clamp convenient length hose to radiator core

outlet opening and attach another suitable length of hose

NOTE

to radiator inlet opening to carry away flushing stream.

Check with the cooling system drain caution plate

on the instrument panel for position of drains, if the

to water line and clamp the nozzle of gun in the hose

vehicle is equipped with such a plate.

attached to the radiator outlet opening (lower).

(2) If necessary, use a wire to keep open any drain

(d) With radiator cap on tight, fill core with water

hole which tends to become clogged.

Turn on compressed air in short blasts to prevent core

(3) Disconnect the radiator overflow return-tank, if

damage.

the vehicle is so equipped.

(e) Allow radiator to fill with water and again apply air

(4) Close the drain cocks, pour water slowly into the

pressure as before. Repeat this process until the water

radiator until the level is within two inches of overflow pipe.

comes out clear and then proceed as in f above.

(5) Replace radiator cap, cover radiator if necessary,

(f) Blow insects and dirt from radiator core air

start the engine, and run it at idling speed until

passages, using water to soften obstructions.

temperature reaches above 180 F but not above 200 F.

Then add cleaning components together into hot radiator

2-16