NUT 1R6484 - Caterpillar

Aftercooler Core Leakage
Illustration 1 g00295702
FT-1984 Aftercooler Testing Group (1) Regulator and valve assembly. (2) Nipple. (3) Relief valve. (4) Tee. (5) Couplers. (6) Aftercooler core assembly. (7) Dust plug. (8) Dust plug. (9) Chain.Aftercooler leakage can cause the following conditions to occur:
Low engine 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 in the aftercooler core can be found through a visual inspection. To check for smaller leaks, use the following procedure:
Disconnect the air pipes from the inlet side of the aftercooler core assembly and from the outlet side of the aftercooler core assembly.
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: The installation of additional hose clamps on hump hoses is recommended. This additional installation should prevent the hump 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) onto 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 pressure of the aftercooler system should not drop more than 35 kPa (5 psi) in 15 seconds.
If the pressure drop is more than the specified amount, follow this procedure:
Use a solution of both soap and water to check all areas for leakage.
Look for air bubbles that will identify possible leaks.
Replace the hoses, 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 you test the aftercooler core assembly, remove the FT-1984 Aftercooler Testing Group. Reconnect the air pipes on both sides of the aftercooler core assembly.Dynamometer Test
In hot ambient temperatures, chassis dynamometer tests for models with an air-to-air aftercooler can add a greater heat load to the jacket water cooling system. Therefore, the temperature of the jacket water cooling system must be monitored. Also, monitor the inlet air temperature, which may need a power correction factor. These other measurements may also need a power correction factor:
Fuel API rating
Fuel temperature
Barometric pressureWith dynamometer tests for engines, use the FT-1438 Dynamometer Testing. This tool uses an air-to-water aftercooler to control the inlet air temperature. This pressure is controlled to 43°C (109°F).