Section III. TROUBLESHOOTING

and block the flow of air Use care to avoid oil spillage on

CAUTION

radiator Use cleaning solvent to remove oil spillage.

g. Coolant in radiator, cylinder block, cylinder

Do not hold air or water hose too close to the

heads, oil coolers, coolant tubes and hoses must flow

radiator or use excessive pressure as damage to

freely without restriction by rust, scale or other sediment.

the radiator core may result.

The cooling system should be cleaned and flushed when

necessary using compound 6850-598-7328.

This

(2) Radiator core cooling fins that have become bent

compound will be used only as necessary and not as a

should be carefully straightened to assure air passage

routine maintenance procedure TB 750-651 establishes

without restriction.

instructions for use.

(3) Overflow tube, when so equipped, should be

h. Shrouds and panels must be in place to assure

cleared using a soft wire probe.

proper air flow and efficient cooling. Engine compartment

(4) Air intake grille and deck screens must be kept

panels, shroud seals, or hull inspection plates will when

free of debris, boxes or baggage that may limit the flow of

removed change the direction of air flow and adversely

air.

Extra items carried should be stowed without

affect the cooling system.

interference to air intake otherwise overheating may result.

(5) Oil spillage on radiator core will tend to hold dust

Section III. TROUBLESHOOTING

trouble occurs and then locate the defect. Do not neglect

2-23.

General

use of any test instruments such as thermostat tester,

cooling system tester, flo tester, combustion tester, and

This section contains a troubleshooting chart (Chart 2-2)

test bench that are available.

Standard automotive

and information for locating and correcting some troubles

theories and principles of operation apply in

which may develop in the radiator. Each symptom of

troubleshooting the radiator. Question vehicle operator to

trouble given is followed by a list of probable causes of the

obtain maximum number of observed symptoms. The

trouble and suggested procedures to be followed to

greater the number of symptoms of troubles that can be

remedy the malfunction.

evaluated, the easier will be the isolation of the defect..

2-24.

Procedures

b. Good operational trouble analysis depends upon

a sound and systematic investigation to determine the

a. If a specific trouble, test, and remedy are not

primary cause of malfunction.

covered herein, proceed to isolate the system in which the

Chart 2-2. Troubleshooting

Malfunction

Probable cases

Corrective action

a. Clogged coolant passages

a Flush or boll radiator (para 3-11)

1. Overheating

b. Disintegrated radiator hose

b. Replace radiator hose (para 1-5)

c. Clogged or bent radiator fins

c. Spray clean, splice or replace radiator fins

(para 3-33)

d. Frozen radiator tubes

d. Clean with acid and boil (para 3-11)

e. Shortage of coolant

e. Check for leaks Tighten clamps Replace

coolant to proper level (para 2-20)

f. Defective or missing thermostat

f. Replace thermostat (see pertinent

maintenance manual)

g. Dirty radiator

g. Drain coolant, clean radiator Add fresh

coolant (para 2-20)

a. Faulty thermostat

a. Replace thermostat (see pertinent

2. Overcooling

maintenance manual)

b. Improper coolant

b. Test coolant mixture Add or remove misture

to bring coolant to proper level (para 2-10)

c. Extremely cold weather

c. Partly cover radiator Close hood louvers

a. Defective or improper radiator cap

a. Replace radiator cap (para 1-10)

3. Loss of or abnormally high

radiator pressure.

b. Collapsed or worn radiator hose

b. Replace hose (para 1-6)

a. Loose radiator hose

a. Tighten hose clamps

4. Loss of coolant

b. Defective or improper radiator cap

b. Replace radiator cap (para 1-10)

2-19