PLATE 9T2557 - Caterpillar

Aftercooler Core Leakage
Illustration 1 g01489974
FT-1984 Aftercooler Testing Group
(1) Regulator and valve assembly
(2) Nipple
(3) Relief valve
(4) Tee
(5) Coupler
(6) Aftercooler
(7) Dust plug
(8) Dust plug
(9) Chain A low power problem in the engine can be the result of aftercooler leakage. Aftercooler system leakage can result in the following problems:
Low power
Low boost pressure
Black smoke
High exhaust temperature
Remove all air leaks from the system to prevent engine damage. In some operating conditions, the engine can pull a manifold vacuum for short periods of time. A leak in the aftercooler or air lines can let dirt and other foreign material into the engine and cause rapid wear and/or damage to engine parts.
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:
Disconnect the air pipes from the inlet and outlet side of the aftercooler core.
Dust plug chains must be installed to the aftercooler 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.
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 being pressurized.
Do not use more than 240 kPa (35 psi) of air pressure or damage to the aftercooler core can be the result.
Install the regulator and valve assembly (1) on the outlet side of the aftercooler core assembly. Also, attach the air supply.
Open the air valve and pressurize the aftercooler to 205 kPa (30 psi). Shut off the air supply.
Inspect all connection points for air leakage.
The aftercooler system's pressure should not drop more than 35 kPa (5 psi) in 15 seconds.
If the pressure drop is more than the specified amount, use a solution of soap and water to check all areas for leakage. Look for air bubbles that will identify possible leaks. Replace the aftercooler core, or repair the aftercooler core, as needed.
To help prevent personal injury when the tooling is removed, relieve all pressure in the system slowly by using an air regulator and a valve assembly.
After the testing, remove the FT-1984 Aftercooler Testing Group. Reconnect the air pipes on both sides of the aftercooler core assembly. Air System Restriction
Pressure measurements should be taken at the air inlet elbow and at the turbocharger outlet.Use the differential pressure gauge of the 1U-5470 Engine Pressure Group. Use the following procedure in order to measure the restriction of the aftercooler:
Connect the vacuum port of the differential pressure gauge to a port in the air inlet elbow.
Connect the pressure port of the differential pressure gauge to a port in the turbocharger outlet.
Record the value. The air lines and the cooler core must be inspected for internal restriction when both of the following conditions are met:
Air flow is at a maximum level.
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