0334521 JOHNSON SCREW, Cover, lower

Turbocharger Failure
Personal injury can result from air pressure.Personal injury can result without following proper procedure. When using pressure air, wear a protective face shield and protective clothing.Maximum air pressure at the nozzle must be less than 205 kPa (30 psi) for cleaning purposes.
If a turbocharger failure occurs, remove the air-to-air aftercooler core. Internally flush the air-to-air aftercooler core with a solvent that removes oil and other foreign substances. Shake the air-to-air aftercooler core in order to eliminate any trapped debris. Wash the aftercooler with hot, soapy water. Thoroughly rinse the aftercooler with clean water and blow dry the aftercooler with compressed air. Blow dry the assembly in the reverse direction of normal air flow. To make sure that the whole system is clean, carefully inspect the system.
Do not use caustic cleaners to clean the air-to-air aftercooler core.Caustic cleaners will attack the internal metals of the core and cause leakage.
Aftercooler Core Leakage
Illustration 1 g01524518
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) Chain
(9) Dust plug 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 (9). These items are included with the FT-1984 Aftercooler Testing Group. Note: Installation of additional hose clamps on the hump hoses is recommended 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 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
Use the following procedure in order to measure the restriction of the aftercooler:
Connect Caterpillar Electronic Technician (ET) to the ECM.
Record channels "Aftertreatment #1 Secondary Air Pressure" and "Boost Pressure".
Run the engine at high idle speed.
Record the values.
Subtract the "Boost Pressure" value from the "Aftertreatment #1 Secondary Air Pressure" value. This value will be your total air pressure drop for the charged system. The lines and cooler core must be inspected for restriction if the engine is operated at high idle with both of the following conditions:
Air flow is at a maximum level.
Total air pressure drop of the charged system exceeds 15 kPa (4.5 in Hg).If a restriction is discovered, proceed with the following tasks, as required:
Clean
Repair
ReplacementDynamometer 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 jacket water cooling system temperature must be monitored. The following measurements may also need a power correction factor:
Inlet air temperature
Fuel API rating
Fuel temperature
Barometric pressureWith dynamometer tests for engines, use the FT-1438 Aftercooler Gp (DYNAMOMETER TEST). This tool allows the water cooled aftercooler to control the inlet air temperature to 43 °C (110 °F).