Cylinder Head Assembly: Service and Repair

CYLINDER HEAD

REMOVAL
1. Disconnect battery negative cables.
2. Raise vehicle on hoist.
3. Drain engine coolant.
4. Disconnect exhaust pipe from turbocharger elbow.
5. Lower vehicle.
6. Disconnect air inlet temperature/pressure sensor.
7. Remove air cleaner housing and snorkel from the vehicle. Cap off turbocharger air inlet to prevent intrusion of dirt or foreign material.
8. Disconnect cab heater core supply and return hoses from the cylinder head and heater pipe.
9. Disconnect turbocharger oil drain tube at rubber hose connection. Cap off open ports to prevent intrusion of dirt or foreign material.
10. Disconnect turbocharger oil supply line at the turbocharger end. Cap off open ports to prevent intrusion of dirt or foreign material.
11. Remove exhaust manifold-to-cylinder head bolts, spacers, heat shield, retention straps, and cab heater plumbing. Remove exhaust manifold and turbocharger from the vehicle as an assembly.
12. Remove cooling fan assembly.
13. Remove accessory drive belt.
14. Remove cooling fan support from cylinder block.
15. Remove upper generator bolt, loosen lower generator bolt, and rotate generator away from cylinder head.
16. Disconnect radiator upper hose from the thermostat housing.
17. Disconnect the Intake Air Temperature, Manifold Air Pressure, and Coolant Temperature sensor connector.
18. Remove the engine harness to cylinder head attaching bolts and P-clips at front of head.





19. Remove the throttle linkage cover (Fig. 8).








20. Remove the six (6) accelerator pedal position sensor assembly-to-cylinder head bracket bolts (Fig. 9) and secure the entire assembly out of the way. Disconnect the APPS connector (Fig. 10). It is not necessary to disconnect the cables from the throttle control assembly.
21. Remove the intake air grid heater wires from the grid heater.
22. Remove engine oil level indicator tube attaching bolt at fuel filter housing bracket and inlet air connection.
23. Remove the charge air cooler-to-air inlet housing pipe.
24. Remove the engine wire harness attaching bolt and wire harness push-in fastener from air inlet housing.
25. Remove the air inlet housing and intake grid heater from the intake manifold cover.
26. Remove the two grid heater harness-to-cylinder head attaching bolts at front of cylinder head.
27. Remove the engine lift bracket from the rear of the cylinder head.
28. Remove the high pressure pump to fuel rail fuel line as follows:
a. Loosen fuel line nuts at fuel pump and at fuel rail.
b. Use a back-up wrench on the fitting at the fuel pump to keep it from loosening.
29. Remove the fuel rail to cylinder head fuel lines as follows:
a. Loosen No. 6 high pressure fuel line shield and position out of way.
b. Loosen the fuel line nuts at the fuel rail and at the cylinder head.
c. Remove the fuel line bracket bolts at the intake manifold cover.
30. Remove the fuel rail as follows:
a. Remove fuel rail pressure sensor connector.
b. Remove banjo fitting at pressure limiting valve.
c. Remove fuel rail bolts and fuel rail.
31. Remove the low pressure lines as follows:
a. Remove the fuel drain banjo fitting on the front side of fuel filter housing.
b. Remove the fuel drain banjo fitting on rear side of fuel filter housing.
c. Remove the fuel drain line support bracket on rear side of filter housing.
d. Remove fuel drain hose.
e. Remove banjo fitting at bottom of fuel filter housing.
f. Disconnect fuel supply hose at lift pump.
32. Disconnect fuel heater, water in fuel sensor, and fuel lift pump connectors.
33. Remove the fuel filter assembly-to-cylinder head bolts and remove filter assembly from vehicle.
34. Remove wire harness P-clip from cylinder head (located behind filter housing).
35. Remove the cylinder head cover.
36. Disconnect rocker housing injector harness connectors.
37. Remove injector harness nuts from injectors.








38. Remove the rocker levers (Fig. 11), cross heads and push rods (Fig. 12). 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.

39. Remove the fuel return line and banjo bolt at the rear of the cylinder head. Be careful not to drop the two (2) sealing washers.
40. Remove the fuel injectors.
41. Remove rocker housing bolts and rocker housing and gasket.
42. Reinstall the engine lift bracket at the rear of cylinder head. Torque to 77 Nm (57 ft. lbs.).
43. Remove twenty six (6) cylinder head-to-block bolts.
44. Attach an engine lift crane to engine lift brackets and lift cylinder head off engine and out of vehicle.
45. Remove the head gasket and inspect for failure.

CLEANING-CYLINDER HEAD

CAUTION: Do not wire brush head surface while fuel injectors are still installed. Fuel injector damage can result.

Remove fuel injector before cleaning (if not already removed during cylinder head removal).

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-PUSHRODS
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 - 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 insert bore, the cylinder head 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. Maximum overall variation end to end is 0.305 mm (0.012 in.) (Fig. 13), and maximum overall variation side to side 0.076 mm (0.003 in.).

DO NOT proceed with the in-chassis overhaul if the cylinder head or block surface is damaged or not flat (within specifications).

Check block surface for distortion. Maximum variation end-to-end is 0.076 mm (0.003 in.), side-to-side 0.051 mm (0.002).

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. 14). 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 in.).

INSPECTION-CROSSHEADS





Inspect the crossheads for cracks and/or excessive wear on rocker lever and valve tip mating surfaces (Fig. 15). Replace any crossheads that exhibit abnormal wear or cracks.

INSPECTION-PUSHRODS





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. 16).





Roll the push rod on a flat work surface with the socket end hanging off the edge (Fig. 17). 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. 18), tighten bolts in the following steps:
a. Torque bolts to 70 Nm (52 ft. lbs.)
b. Back off 360 degrees in sequence
c. Torque bolts to 105 Nm (77 ft. lbs.)
d. Re-check all bolts to 105 Nm (77 ft. lbs.)
e. Tighten all bolts an additional 1/4 turn (90°)





4. Install push rods into their original locations (Fig. 19). Verify that they are seated in the tappets.
5. Lubricate valve stem tips and install the crossheads in their original locations.





6. Lubricate the rocker arms and pedestals and install them in their original locations (Fig. 20). Install the bolts and torque them to 36 Nm (27 ft. lbs.).
7. Verify that the valve lash settings are maintained.
8. Inspect rocker housing gasket for cuts and proper installation into groove. Replace if damaged.
9. Install rocker housing and bolts. Tighten to 24 Nm (18 ft. lbs.).
10. Install fuel injector.
11. Install fuel injector tube and fuel injector tube nut. Torque to 50 Nm (37 ft. lbs.).
12. Install injector harness nuts. Tighten to 1.5 Nm (13 in. lbs.).
13. Install cylinder head cover.
14. Install wire harness P-clip to cylinder head behind filter housing 24 Nm (18 ft. lbs.).
15. Connect the IAT and MAP sensor connector.
16. Install the fuel filter canister assembly and torque mounting bolts to 24 Nm (18 ft. lbs.).
17. Connect fuel lift pump, MAP sensor, and fuel heater.
18. Remove the engine lift bracket at rear of cylinder head.

CAUTION: Failure to follow procedure will result in fuel leaks and/or fuel system failure.

19. Install the fuel rail and high pressure fuel lines as follows:
a. Hand tighten fuel rail bolts.
b. Hand tighten fuel drain line to pressure limiting valve. Hand tighten at fuel filter housing.
c. Hand tighten fuel rail-to-cylinder head lines.
d. Install fuel line brace bolts-to-intake manifold finger tight.
e. Hand tighten fuel pump to fuel rail line.
f. Torque fuel line nuts at cylinder head to 30 Nm (22 ft. lbs.).
g. Torque fuel line nuts at fuel rail to 30 Nm (22 ft. lbs.)
h. Torque fuel pump to fuel rail line to 30 Nm (22 ft. lbs.).
i. Torque fuel drain banjo bolt at pressure limiting valve and front of fuel filter housing to 24 Nm (18 ft. lbs.).
j. Torque fuel line brace bolts to 24 Nm (18 ft. lbs.).
k. Torque rail bolts to 24 Nm (18 ft. lbs.).
1. Connect fuel pressure sensor.
20. Install the engine lift bracket at the rear of cylinder head. Torque to 77 Nm (57 ft. lbs.).
21. Reposition number 6 fuel line shield and torque to 43 Nm (32 ft. lbs.).
22. 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.).
23. Connect fuel return line at back of cylinder head hand tight.
24. Connect fuel return line at filter housing hand tight.
25. Torque banjo connections at cylinder head and fuel filter housing to 24 Nm (18 ft. lbs.)
26. Install bracket to rear of filter housing. Torque to 24 Nm (18 ft. lbs.).
27. Using new gaskets, install the intake grid heater and air inlet housing. Torque bolts to 24 Nm (18 ft. lbs.).
28. Install wire harness P-clip and push on clip to air inlet housing.
29. Connect engine oil level indicator tube at fuel filter housing and at air inlet housing.
30. Connect the APPS connector.
31. Install the APPS assembly to the cylinder head bracket and torque bolts to 24 Nm (18 ft. lbs.).
32. Install the throttle linkage cover.
33. Install the charge air cooler-to-air inlet housing duct assembly. Torque all clamps to 11 Nm (100 in. lbs.).
34. Connect intake grid heater wires.
35. Secure engine harness to front of cylinder head with bolt at four locations.
36. Connect engine coolant temperature sensor connector.
37. Connect radiator upper hose to thermostat housing.
38. Rotate generator into position. Install upper bolt and torque upper and lower bolts.
39. Install wire harness push-on clip below bracket.
40. Install wire harness P-clip to top of bracket.
41. Install fan support and torque to 32 Nm (24 ft. lbs.).
42. Install cooling fan/drive and torque to 33 Nm (24 ft. lbs.).
43. Install accessory drive belt.
44. Install exhaust manifold/turbocharger assembly, using new gaskets. Start all bolts/spacers by hand. Torque bolts to 43 Nm (32 ft. lbs.).
45. Install exhaust manifold heat shield. Torque to 24 Nm (18 ft. lbs.).
46. Install exhaust bolt retention straps across cylinders 5 & 6.
47. Connect turbocharger oil drain tube. Torque to 8 Nm (71 in. lbs.).
48. Perform the turbocharger pre-lube procedure.
49. Connect the turbocharger oil supply line. Torque to 24 Nm (18 ft. lbs.).
50. Install air cleaner housing and duct.
51. Connect air inlet temperature/pressure sensor.
52. Raise vehicle on hoist.
53. Install exhaust pipe to turbocharger elbow. Torque bolts to 8 Nm (72 in. lbs.).
54. Lower vehicle.
55. Fill engine coolant.
56. Start engine and check for leaks.