Intake Manifold: Service and Repair

Turbocharged Engine Components:

REMOVAL
1. Disconnect battery and drain cooling system.
2. Raise and support vehicle.
3. Disconnect exhaust pipe at articulated joint and disconnect oxygen sensor at electrical connectors.
4. Remove turbocharger to block support bracket.
5. Loosen oil drain back tube connector hose clamps and move tube down on block fitting.
6. Disconnect turbocharger coolant inlet tube at cylinder block and disconnect tube support bracket.
7. Lower vehicle.

Fig. 27 Air cleaner box & support, hoses, & throttle body adapter:

8. Remove air cleaner assembly including throttle body adapter, hose, and air cleaner box with support bracket.

Fig. 28 Accelerator linkage & throttle body:

9. Disconnect accelerator linkage, throttle body electrical connector, and vacuum hoses.
10. Remove four bracket to intake manifold screws and two bracket to heat shield retaining clips, then lift and secure fuel rail, with injectors, wiring harness, and fuel lines intact, up out of the way.
11. Disconnect turbocharger oil feed line at oil sending unit tee.
12. Disconnect upper radiator hose at thermostat housing.
13. Remove cylinder head with manifolds and turbocharger as an assembly as described under "Cylinder Head & Valve Assembly."
14. With assembly on the bench, loosen upper turbocharger discharge hose end clamp DO NOT DISTURB CENTER DESIRABLE RETAINING CLAMP. Remove 3 throttle body to intake manifold screws and remove throttle body assembly.
15. Disconnect turbocharger coolant return tube at water box and retaining bracket on cylinder head.
16. Remove 3 heat shield to intake manifold screws and remove heat shield.
17. Remove 4 nuts attaching turbocharger to exhaust manifold and remove turbocharger assembly.
18. Remove intake manifold retaining screws and washer assemblies and remove intake manifold.
19. Remove exhaust manifold retaining nuts and remove exhaust manifold.

CLEANING & INSPECTION
1. Discard gasket and clean all gasket surfaces on both manifolds and cylinder head.
2. Test gasket surfaces for flatness with straight edge. Surface must be flat within .006 in. per foot (0.15 mm per 300 mm) of manifold length.
3. Inspect manifolds for cracks and distortion.

INSTALLATION
1. Install new two-sided Grafoil or equivalent, intake/exhaust manifold gasket. DO NOT APPLY SEALER.
2. Set exhaust manifold in place. Apply antiseize compound such as Loctite 771-64 or equivalent to threads, install and torque retaining nuts starting at center and progressing outward in both directions to 200 in. lbs. (23 Nm). Repeat this procedure until all screws are at specified torque.

Intake & Exhaust Manifolds:

3. Position intake manifold, install and torque retaining screw and washer assemblies starting at center and progressing outward in both directions to 200 in. lbs. (23 Nm). Repeat this procedure until all screws are at specified torque.
4. Connect turbocharger outlet to intake manifold inlet tube and position turbocharger in place on exhaust manifold, apply anti-seize compound such as Loctite 771-64 or equivalent to threads and torque retaining nuts to 40 ft. lbs. (54 Nm). Tighten connector tube clamps to 30 in. lbs. (3 Nm).
5. Install coolant return tube into water box connector and tighten tube nut to 30 ft. lbs. (41 Nm) torque. Install tube support bracket to cylinder head.
6. Install heat shield to intake manifold and tighten 3 attaching screws to 105 in. lbs. (12 Nm).
7. Install throttle body air horn into turbocharger inlet tube and install 3 throttle body to intake manifold screws to 250 in. lbs. (28 Nm). Tighten tube clamp to 30 in. lbs. (3 Nm).
8. Install cylinder head assembly.
9. Re-connect turbocharger oil feed line to oil sending unit tee and bearing housing, if disconnected. Tighten tube nut(s) to 125 in. lbs. (14 Nm).
10. Install air cleaner assembly and reconnect vacuum lines and accelerator cables.
11. Reposition fuel rail, install and tighten 4 bracket screws to 250 in. lbs. (28 Nm) and install 2 air shield to bracket retaining clips.
12. Connect turbocharger inlet coolant tube to cylinder block. Tighten tube nut to 30 ft. lbs. (41 Nm). Install tube support bracket.
13. Install turbocharger housing to block support bracket and install screws finger tight. Tighten block screw FIRST to 40 ft. lbs. (54 Nm) then, tighten screw to turbocharger housing to 20 ft. lbs. (27 Nm).
14. Reposition drain back tube (hose) connector and tighten hose clamps. Reconnect exhaust pipe.
15. Connect upper radiator hose to thermostat housing. Tighten hose clamp to 35 in. lbs. (41 Nm).
16. Fill cooling system.