Air System Restriction

TM 9-2320-312-24-2

Testing and Adjusting Section

Air System Restriction

A large leak of the aftercooler core can often be

found by making a visual inspection. To check for

smaller leaks, use the following procedure:

1. Disconnect the air pipes from the inlet and outlet

side of the aftercooler core.

Dust plug chains must be installed to the after-

cooler core or to the radiator brackets to prevent

possible injury while you are testing. Do not stand

in front of the dust plugs while you are testing.

2. Install couplers (5) on each side of the aftercooler

core. Also, install dust plugs (7) and (8). These

items are included with the FT-1984 Aftercooler

Testing Group.

Note: Installation of additional hose clamps on the

hump hoses is recommended in order to prevent

the hoses from bulging while the aftercooler core is

g00581364

Illustration 61

being pressurized.

Pressure measurements should be taken at the inlet

NOTICE

manifold (1) and at the turbocharger outlet (2).

Do not use more than 240 kPa (35 psi) of air pressure

or damage to the aftercooler core can be the result.

Use the differential pressure gauge of the 1U-5470

Engine Pressure Group or use the 198-4240

Pressure Indicator Tool Gp. Use the following

3. Install the regulator and valve assembly (1) on

procedure in order to measure the restriction of the

the outlet side of the aftercooler core assembly.

aftercooler:

Also, attach the air supply.

1. Connect the vacuum port of the differential

4. Open the air valve and pressurize the aftercooler

pressure gauge to port (1).

to 205 kPa (30 psi). Shut off the air supply.

2. Connect the pressure port of the differential

5. Inspect all connection points for air leakage.

pressure gauge to port (2).

6. The aftercooler system's pressure should not

3. Record the value.

drop more than 35 kPa (5 psi) in 15 seconds.

The air lines and the cooler core must be inspected

7. If the pressure drop is more than the specified

for internal restriction when both of the following

amount, use a solution of soap and water to

conditions are met:

check all areas for leakage. Look for air bubbles

that will identify possible leaks. Replace the

Air flow is at a maximum level.

aftercooler core, or repair the aftercooler core,

as needed.

Total air pressure drop of the charged system

exceeds 16.9 kPa (5 in Hg).

If a restriction is discovered, proceed with the

To help prevent personal injury when the tooling is

following tasks, as required:

removed, relieve all pressure in the system slowly

by using an air regulator and a valve assembly.

Clean

Repair

8. After the testing, remove the FT-1984 Aftercooler

Testing Group. Reconnect the air pipes on both

Replacement

sides of the aftercooler core assembly.