Check the fan and/or the fan shroud

TM 9-2320-312-24-2

Testing and Adjusting Section

12. Check the cooling system hoses and clamps.

d. Ensure that the radiator size is according

Damaged hoses with leaks can normally be

to the OEM specifications. An undersized

seen. Hoses that have no visual leaks can soften

radiator does not have enough area for the

during operation. The soft areas of the hose can

effective release of heat. This may cause

become kinked or crushed during operation.

the engine to run at a temperature that is

These areas of the hose can cause a restriction

higher than normal. The normal temperature

in the coolant flow. Hoses can become soft.

is dependent on the ambient temperature.

Also, hoses can get cracks after a period of

time. The inside of a hose can deteriorate, and

9. Check the filler cap. A pressure drop in the

the loose particles of the hose can cause a

radiator can cause the boiling point to be lower.

restriction of the coolant flow. Refer to Operation

This can cause the cooling system to boil. Refer

and Maintenance Manual, "Hoses and Clamps -

to Testing and Adjusting, "Cooling System - Test".

Inspect/Replace".

10. Check the fan and/or the fan shroud.

13. Check for a restriction in the air inlet system.

A restriction of the air that is coming into the

a. Ensure that the fan is installed correctly.

engine can cause high cylinder temperatures.

Improper installation of the fan can cause

High cylinder temperatures can cause higher

engine overheating.

than normal temperatures in the cooling system.

Refer to Testing and Adjusting, "Air Inlet and

b. The fan must be large enough to send air

Exhaust System - Inspect".

through most of the area of the radiator

core. Ensure that the size of the fan and the

a. If the measured restriction is higher than the

position of the fan are according to the OEM

maximum permissible restriction, remove the

specifications.

foreign material from the engine air cleaner

element or install a new engine air cleaner

c. The fan shroud and the radiator baffling must

element. Refer to Operation and Maintenance

be the proper size. The fan shroud and the

Manual, "Engine Air Cleaner Element -

radiator baffling must be positioned correctly.

Clean/Replace".

The size of the fan shroud and the position

of the fan shroud should meet the OEM

b. Check the air inlet system for a restriction

specifications. The size of the radiator baffling

again.

and the position of the radiator baffling should

meet the OEM specifications.

c. If the measured restriction is still higher than

the maximum permissible restriction, check

11. Check for loose drive belts.

the air inlet piping for a restriction.

a. A loose fan drive belt will cause a reduction

14. Check for a restriction in the exhaust system.

in the air flow across the radiator. Check the

A restriction of the air that is coming out of the

fan drive belt for proper belt tension. Adjust

engine can cause high cylinder temperatures.

the tension of the fan drive belt, if necessary.

Refer to Operation and Maintenance Manual,

a. Make a visual inspection of the exhaust

"Belt - Inspect".

system. Check for damage to exhaust

piping. Also, check for a damaged muffler.

b. A loose water pump drive belt will cause a

If no damage is found, check the exhaust

reduction in coolant flow through the radiator.

system for a restriction. Refer to Testing and

Check the water pump drive belt for proper

Adjusting, "Air Inlet and Exhaust System -

belt tension. Adjust the tension of the water

Inspect".

pump drive belt, if necessary. Refer to

Operation and Maintenance Manual, "Belt -

b. If the measured restriction is higher than the

Inspect".

maximum permissible restriction, there is a

restriction in the exhaust system. Repair the

exhaust system, as required.

c. Ensure that the exhaust gas is not being

drawn into the cooling air inlet.