Removing elements of the Cummins ISF3.8 air intake system

The air intake system components are removed during a major overhaul or when faults are found.

Removal and installation of the turbocharger

1. Prepare the vehicle for the work. Disconnect the battery negative terminal.
2. Disconnect the charge air cooler pipe.
3. Remove the oil supply pipe.

   Note: hold the union to prevent it from turning with a spanner when loosening the nut.

   • a) Remove the oil supply pipe from the cylinder block union (1).
   • b) Remove the oil supply pipe from the bearing housing union (2).

   

4. Remove the oil return pipe.
   • a) Unscrew the oil return pipe mounting bolts.
   • b) If necessary, remove the clamps from the oil return pipe connections.
   • c) If necessary, pull the hose out of the unions.
   • d) Pull the oil return pipe union out of the cylinder block.
   • e) Remove the O-rings.

   

5. Remove the exhaust system pipe.

   

6. Disconnect the compressor inlet pipe.
7. Remove the turbocharger.

   Note: this assembly weighs more than 23 kg; to avoid injury, work with an assistant.

   Caution! After removing the turbocharger, determine the gasket type. Some gaskets have a divider in the middle. Fitting an unsuitable gasket will cause a turbocharger fault.

   

8. Loosen the clamp and remove the compressor outlet pipe with its gasket.

   

9. Unscrew the four turbocharger mounting nuts.
10. Remove the turbocharger and gasket. Note: do not reuse the turbocharger gasket.
11. Clean the turbocharger surfaces with solvent or steam to remove deposits and gasket residue. Dry with compressed air.

    

12. Check the turbocharger housing for cracks and damage.

    

13. If the turbocharger has been seriously damaged, check the charging system for debris, dirt and oil. Clean the air supply system, including the charge air cooler.

    

Installation of the turbocharger

1. Apply a thin layer of high-temperature anti-seize compound to the turbocharger mounting studs.
2. Fit a new gasket of the same type as the one removed and install the turbocharger.
3. Install and tighten the four mounting nuts.

   Note: the torque values given take into account the use of anti-seize compound as a lubricant. Tightening torque: 24 N·m.

4. Install the oil return pipe:
   • a) Fit the O-rings onto the oil return pipe.
   • b) Lubricate the O-rings with engine oil.
   • c) Insert the drain line into its fitting. The seal rings must seat fully in their bores.
   • d) Connect the oil return pipe flange with a new gasket to the bearing housing and tighten the bolts. Tightening torque: 10 N·m.

   

5. Pour engine oil into the turbocharger.

   

   • a) Pour 60–90 ml of clean engine oil through the turbocharger oil supply pipe opening.
   • b) Turn the turbocharger wheel so that the oil passes into the bearing housing.
6. Install the outlet pipe, band clamp and a new O-ring on the turbocharger compressor outlet. Tighten the clamp. Tightening torque: 10 N·m.

   

7. Connect the charge air cooler pipes.
8. Install and tighten the oil supply pipe:
   • a) Fit new copper washers or O-rings.
   • b) Connect the oil supply pipe to the cylinder block union (1) and to the bearing housing union (2).
   • c) Tighten the mounting nuts. Tightening torque: 28 N·m.

   

9. Install the exhaust system pipe.
10. Install the inlet pipe on the compressor.
11. Connect the batteries.
12. Start the engine and make sure there are no leaks.

Turbocharger wastegate actuator

Initial checks

1. Check the flexible hose between the actuator connection and the compressor housing for damage and secure fastening. If damaged, replace the hose and clamps.

   

2. Check the actuator support bracket, rod and lever for damage.

   

Enlargement of the actuator rod bore will require replacement of the actuator. If the support bracket, rod or wastegate actuator lever is deformed, replace the bent part without fail.

Removal of the wastegate actuator

Note: before removal, mark the orientation of the wastegate actuator housing union relative to the support bracket.

1. Remove the turbocharger.
2. Remove the wastegate actuator:
   • a) Remove the retaining ring from the control lever.
   • b) Disconnect the hose from the wastegate actuator housing.

   

3. Disconnect the actuator rod from the wastegate lever.

   To do this, increase the pressure in the actuator housing until the rod starts to move. Use an air pressure regulator fitted with a gauge.

   Disconnect the actuator rod from the wastegate lever pin.

   

   Note: if the actuator diaphragm is cracked and does not hold pressure, pull the rod by hand against the actuator spring force to release it from the wastegate lever pin.

   

4. Loosen the actuator housing mounting bolts, disconnect the air supply hose and remove the assembly from the support bracket.

Wastegate actuator leak test

1. Disconnect the hose from the wastegate actuator housing.
2. Connect and secure the hose between an adjustable compressed air source and the actuator.

   

3. Gradually increasing the pressure to 300 kPa supplied to the actuator from the adjustable compressed air source, check whether the actuator rod moves.

   Note: if the actuator housing is in good order, no air leak noise should be heard.

   

4. If the rod does not move, remove the retaining ring and disconnect the rod from the wastegate lever pin.

   

5. Supply air under pressure to the actuator housing and check whether the rod moves. If there is no movement, replace the wastegate actuator.
6. If the actuator rod moves, rock the wastegate lever and check the smoothness of its movement.

   If the wastegate lever seizes, spray penetrating lubricant onto its joint and try to rock and free the lever. If it cannot be freed, replace the turbocharger.

   

7. If the lever has been freed and now moves smoothly, connect the actuator rod and check its movement under air pressure.

   

Installation of the wastegate actuator

1. Fit the link rod onto the wastegate lever pin.
2. Turn the spacer so that its ridge is visible, press the wastegate lever against the rod, then lay the actuator along the support bracket.

   Note: do not insert the two studs into the holes at this stage.

   

3. Adjust the actuator rod length by removing the actuator from the turbocharger. By turning the rod end, position the actuator so that the studs can be inserted into the holes with a slight clearance.

   

4. With correct adjustment, the lower part of the actuator sits on the bracket with a clearance of less than 0.5 mm.

   

5. Insert the actuator mounting studs into the bracket holes.
6. Fit the actuator rod onto the wastegate lever pin. Install the retaining ring.
7. Tighten the mounting nuts. Tightening torque: 8 N·m.

   

8. Tighten the actuator rod lock nut while holding the rod end. Tightening torque: 8 N·m.

   

9. Connect the hose to the actuator union, fit a new clamp.

Intake manifold

Removal of the intake manifold

1. Disconnect the lead from the battery negative terminal.
2. Remove the charge air bypass pipe.
3. Remove the high-pressure fuel lines.
4. Remove the fuel supply hoses.
5. Remove the fuel accumulator.
6. Remove the air intake pipe adapter. Tightening torque: 10 N·m.
7. Remove the intake air heater of the cold start system.
8. Remove the boost pressure sensor and intake air temperature sensor as an assembly.
9. Drain the coolant.
10. Remove the coolant bypass pipe with the O-rings by unscrewing the bolt. Tightening torque: 24 N·m.

    

Models with a closed crankcase ventilation system

11. Remove the crankcase ventilation system valve.
12. Remove the intake manifold.

    Note: make sure that gasket residue and other foreign particles do not enter the cylinder head intake ports.

    • a) Unscrew the intake manifold mounting bolts from the cylinder head, remove the intake manifold.

    

    • b) Remove the gasket.
    • c) Tape over the ports in the cylinder head to prevent dirt from entering.

Installation of the intake manifold

1. Install the intake manifold and screw in the bolts. Apply sealant (No. 3824041) to the bolt threads before installation.

   Note: if the intake manifold is fitted with a gasket, replace the gasket. If the intake manifold is mounted on sealant, remove the old sealant and apply new heat-resistant RTV sealant (No. 3164070).

   Tightening torque: 24 N·m.

2. Further installation is carried out in the reverse order of removal.
3. Start the engine and make sure there are no leaks.

The above materials cover the removal and installation of the air intake system components of the Cummins ISF3.8 engine: turbocharger, turbocharger wastegate actuator and intake manifold. The material is intended for diagnostics, fault-finding and repair of the air intake system.