Cylinder Head Assembly: Service and Repair
REMOVAL1. Disconnect battery negative cables.
2. Raise vehicle on hoist.
3. Drain engine coolant.
4. Disconnect exhaust pipe from turbocharger elbow (Fig. 14).
5. Lower vehicle.
6. Remove air cleaner housing and snorkel from the vehicle. Cap off turbocharger air inlet to prevent intrusion of dirt or foreign material.
7. Disconnect cab heater core supply and return hoses from the cylinder head and heater pipe.
8. Disconnect turbocharger oil drain tube at rubber hose connection. Cap off open ports to prevent intrusion of dirt or foreign material.
9. Disconnect turbocharger oil supply line at the turbocharger end. Cap off open ports to prevent intrusion of dirt or foreign material.
10. Remove exhaust manifold-to-cylinder head bolts and spacers. Remove exhaust manifold and turbocharger from the vehicle as an assembly.
11. Remove accessory drive belt.
12. Remove generator upper bracket.
13. Disconnect radiator upper hose from the thermostat housing.
14. Disconnect the coolant temperature sensor connector.
15. Remove the engine harness to cylinder head attaching bolt at front of head.
16. Remove the engine harness ground fastener at front of head below the thermostat housing.
Figure 16
Figure 17
18. Remove the six 6 accelerator pedal position sensor assembly-to-cylinder head bracket bolts (Fig. 16) and secure the entire assembly out of the way. Disconnect the APPS connector (Fig. 17). It is not necessary to disconnect the cables from the throttle control assembly.
19. Remove the intake air grid heater wires from the grid heater.
20. Remove engine oil level indicator tube attaching bolt from the air inlet housing.
21. Remove the charge air cooler-to-air inlet housing pipe.
22. Remove the air inlet housing and intake grid heater from the intake manifold cover.
23. Remove the engine lift bracket from the rear of the cylinder head.
Figure 18
Figure 19
24. Remove the high pressure fuel lines (Fig. 18) (Fig. 19) from the engine as follows:
a. Remove all injection line-to-intake manifold cover support bracket bolts.
b. Loosen the #1, 2, and 4 cylinder high pressure lines at the injection pump.
c. Loosen the #1, 2, and 4 cylinder high pressure lines at the cylinder head.
d. Remove the #1, 2, and 4 cylinder high pressure line bundle from the engine.
e. Loosen the #3, 5, and 6 cylinder high pressure lines at the injection pump.
f. Loosen the #3, 5, and 6 cylinder high pressure lines at the cylinder head.
g. Remove the #3, 5, and 6 cylinder high pressure line bundle from the engine.
25. Remove the lift pump-to-fuel filter low pressure line.
26. Remove the fuel filter-to-injection pump low pressure line.
27. Disconnect the water-in-fuel and fuel heater connectors.
28. Remove the fuel filter assembly-to-manifold cover bolts and remove filter assembly from vehicle.
29. Disconnect the Intake Air Temperature and Manifold Air Pressure sensor connectors (Fig. 20).
30. Remove the cylinder head cover (Fig. 21).
Figure 22
Figure 23
31. Remove the rocker levers (Fig. 22), cross heads and push rods (Fig. 23). Mark each component so they can be installed in their original positions.
NOTE: The #5 cylinder exhaust and the #6 cylinder intake and exhaust push rods are removed by lifting them up and through the provided cowl panel access holes. Remove the rubber plugs to expose these relief holes.
32. Remove the fuel return line banjo bolt at the rear of the cylinder head (Fig. 24). Be careful not to drop the two 2 sealing washers.
33. Reinstall the engine lift bracket at the rear of cylinder head.
34. Remove twenty six 26 cylinder head-to-block bolts.
35. Attach an engine lift crane to engine lift brackets and lift cylinder head off engine and out of vehicle.
36. Remove the head gasket and inspect for failure.
CLEANING
CLEANING-CYLINDER HEAD
CAUTION: Do not wire brush head surface while fuel injectors are still installed. Fuel injector damage can result.
Clean the carbon from the injector nozzle seat with a nylon or brass brush.
Scrape the gasket residue from all gasket surfaces.
Wash the cylinder head in hot soapy water solution (88° C or 140° F).
After rinsing, use compressed air to dry the cylinder head.
Polish the gasket surface with 400 grit paper. Use an orbital sander or sanding block to maintain a flat surface.
CLEANING-CROSSHEADS
Clean all crossheads in a suitable solvent. If necessary, use a wire brush or wheel to remove stubborn deposits. Rinse in hot water and blow dry with compressed air.
CLEANING-PUSH RODS
Clean the pushrods in a suitable solvent. Rinse in hot water and blow dry with compressed air. If necessary, use a wire brush or wheel to remove stubborn deposits.
INSPECTION
INSPECTION-CYLINDER HEAD
Inspect the cylinder head for cracks in the combustion surface. Pressure test any cylinder head that is visibly cracked. A cylinder head that is cracked between the injector bore and valve seat can be pressure tested and reused if OK; however, if the crack extends into the valve seat, the valve seat must be replaced.
Visually inspect the cylinder block and head combustion surfaces for localized dips or imperfections. Check the cylinder head and block combustion surfaces for overall out-of-flatness. If either the visual or manual inspection exceeds the limits, then the head or block must be surfaced.
Check the top surface for damage caused by the cylinder head gasket leaking between cylinders.
Inspect the block and head surface for nicks, erosion, etc.
Check the head distortion (Fig. 25). The distortion of the combustion deck face is not to exceed 0.010 mm (0.0004 inch) in any 50.8 mm (2.00 inch) diameter. Overall variation end to end or side to side 0.30 mm (0.012 inch).
DO NOT proceed with the in-chassis overhaul if the cylinder head or block surface is damaged or not flat (within specifications).
Visually inspect the cylinder head bolts for damaged threads, corroded/pitted surfaces, or a reduced diameter due to bolt stretching.
If the bolts are not damaged, their "free length" should be measured using the cap screw stretch gauge provided with the replacement head gasket. Place the head of the bolt against the base of the slot and align the bolt with the straight edge of gauge (Fig. 26). If the end of the bolt touches the foot of the gauge, the bolt must be discarded. The maximum bolt free length is 132.1 mm (5.200 inch).
INSPECTION-CROSSHEADS
Inspect the crossheads for cracks and/or excessive wear on rocker lever and valve tip mating surfaces (Fig. 27). Replace any crossheads that exhibit abnormal wear or cracks.
INSPECTION-PUSH RODS
Inspect the push rod ball and socket for signs of scoring. Check for cracks where the ball and the socket are pressed into the tube (Fig. 28).
Roll the push rod on a flat work surface with the socket end hanging off the edge (Fig. 29). Replace any push rod that appears to be bent.
INSTALLATION
WARNING: THE OUTSIDE EDGE OF THE HEAD GASKET IS VERY SHARP. WHEN HANDLING THE NEW HEAD GASKET, USE CARE NOT TO INJURE YOURSELF.
1. Install a new gasket with the part number side up, and locate the gasket over the dowel sleeves.
2. Using an engine lifting crane, lower the cylinder head onto the engine.
3. Lightly lubricate head bolts with engine oil and install. Using the sequence shown in (Fig. 30), tighten bolts in the following steps:
a. Torque bolts to 80 Nm (59 ft. lbs.)
b. Torque bolts to 105 Nm (77 ft. lbs.)
c. Re-check all bolts to 105 Nm (77 ft. lbs.)
d. Tighten all bolts an additional 1/4 turn (90°)
4. Connect fuel return line at rear of head (Fig. 24). Install both sealing washers and torque banjo bolt to 24 Nm (18 ft. lbs.).
5. Install push rods into their original locations (Fig. 31). Verify that they are seated in the tappets.
6. Lubricate valve stem tips and install the crossheads in their original locations.
7. Lubricate the rocker arms and pedestals and install them in their original locations (Fig. 32). Install the bolts and torque them to 36 Nm (27 ft. lbs.).
8. Verify that the valve lash settings are maintained.
9. Install cylinder head cover (Fig. 33).
10. Connect the IAT and MAP sensor connectors.
11. Install the fuel filter canister assembly and torque mounting bolts to 24 Nm (18 ft. lbs.).
12. Connect the lift pump to fuel filter low pressure line. Torque fittings to 24 Nm (18 ft. lbs.).
13. Connect the Water-in-Fuel and Fuel Heater Element connectors at the filter assembly.
14. Remove the engine lift bracket at rear of cylinder head.
15. Install the high pressure fuel lines (Fig. 18) (Fig. 19) as follows:
a. Lubricate the threads (both ends) of the high pressure line nuts with diesel fuel or engine oil.
b. Install the rear line bundle (cyls. #3, 5, and 6), and tighten the threads at the head and pump by hand.
c. Torque the connections at the cylinder head first. Torque connections to 38 Nm (28 ft. lbs.).
d. Torque the line connections at the injection pump to 24 Nm (18 ft. lbs.).
e. Install the front line bundle (cyls. #1, 2, and 4) following the same procedure used for the rear line bundle.
f. Torque the connections at the cylinder head first. Torque connections to 38 Nm (28 ft. lbs.).
g. Torque the line connections at the injection pump to 24 Nm (18 ft. lbs.).
h. Install the injection line support bracket to intake cover/cylinder head bolts and torque to 24 Nm (18 ft. lbs.).
16. Install the engine lift bracket at the rear of cylinder head. Torque to 77 Nm (57 ft. lbs.).
17. Install the fuel filter to injection pump low pressure line. Inspect and replace sealing washers if necessary. Torque banjo bolts to 24 Nm (18 ft. lbs.).
18. Using new gaskets, install the intake grid heater and air inlet housing. Torque bolts to 24 Nm (18 ft. lbs.).
19. Connect the APPS connector (Fig. 17).
20. Install the APPS assembly. to the cylinder head bracket and torque bolts to 12 Nm (105 inch lbs.).
21. Install the throttle linkage cover (Fig. 15).
22. Install the charge air cooler-to-air inlet housing duct assembly. Torque all clamps to 11 Nm (100 inch lbs.).
23. Connect intake grid heater wires.
24. Fasten engine harness to front of cylinder head with bolt.
25. Install engine harness ground wire and torque bolt to 24 Nm (18 ft. lbs.).
26. Connect engine coolant temperature sensor connector.
27. Connect radiator upper hose to thermostat housing.
28. Install generator upper bracket and torque bolts to 41 Nm (31 ft. lbs.).
29. Install accessory drive belt.
30. Install exhaust manifold/turbocharger assembly. and start all bolts/spacers by hand. Torque bolts to 43 Nm (32 ft. lbs.).
31. Connect turbocharger oil drain tube.
32. Perform the turbocharger pre-lube procedure.
33. Connect the turbocharger oil supply line.
34. Install air cleaner housing and duct.
35. Raise vehicle on hoist.
36. Install exhaust pipe to turbocharger elbow (Fig. 14). Torque bolts to 34 Nm (25 ft. lbs.).
37. Lower vehicle.
38. Fill engine coolant.
39. Start engine and check for leaks.