Intake manifold and Valve Lifter Oil Manifold (VLOM) — removal and installation
Removal
1. Disconnect the cable from the negative the ruminal of the battery (see Engine electrical systems). Relieve the fuel system pressure (see Fuel and exhaust systems).
2. Refer to (see Fuel and exhaust systems) and remove the air filter housing outlet duct
3. Refer to (see Engine electrical systems) and remove the alternator.
4. Label, then disconnect all of the engine wiring harnesses that interfere with intake manifold removal. Also detach all the harness retainers and clips. Move the detached harnesses aside and secure them out of the way.
Note: Clear labeling will make the assembly procedure go smoothly and quickly.
5. Disconnect the power brake vacuum hose from the booster.
6. Disconnect the hose from the canister purge solenoid (see Emissions and engine control systems). Disconnect the fuel line from the fuel rail (see Fuel and exhaust systems). Disconnect the PCV hose from the intake manifold.
7. Disconnect any remaining electrical connectors or vacuum hoses connected to the intake manifold or throttle body.
8. Loosen the intake manifold mounting bolts in 1/4-turn increments in the reverse order of the tightening sequence until they can be removed by hand (see illustrations 7.15a or 7.15b). The manifold will probably be stuck to the cylinder heads and force may be required to break the gasket seal. A pry bar can be positioned between the front of the manifold and the valley tray to break the bond made by the gasket.
Caution: Do not pry between the manifold and the heads or damage to the gasket sealing surfaces may result and vacuum leaks could develop. Also, don’t use too much force — the manifold is made of a plastic composite and could crack.
9. Slide the manifold forward and disconnect the wiring harness fasteners, then remove the intake manifold. As the manifold is lifted from the engine, be sure to check for and disconnect anything still attached to the manifold. The Valve Lifter Oil Manifold (VLOM) assembly can be removed at this time (see illustrations).
7.9a Valve Lifter Oil Manifold (VLOM) assembly mounting bolts
7.9b The Valve Lifter Oil Manifold (VLOM) gasket (A) can be re- used if it’s in good condition. Don’t pick up the assembly by the electrical lead frame (B)
10. On 6.0L models, if the manifold is being replaced, remove the fuel rail and injectors from the intake manifold (see Fuel and exhaust systems).
installation
Note: The mating surfaces of the cylinder heads, block and manifold must be perfectly clean when the manifold is installed.
11. Carefully remove all traces of old gasket material. Note that the intake manifold is made of a composite material and the cylinder heads on some engines are made of aluminum; therefore, aggressive scraping is not suggested and will damage the sealing surfaces. After the gasket surfaces are cleaned and free of any gasket material, wipe the mating surfaces with a cloth saturated with safety solvent. If there is old sealant or oil on the mating surfaces when the manifold is installed, oil or vacuum leaks may develop. Use a vacuum cleaner to remove any gasket material that falls into the intake ports in the heads.
12. Use a tap of the correct size to chase the threads in the bolt holes, then use compressed air (if available) to remove the debris from the holes.
Warning: Wear safety glasses or a face shield to protect your eyes when using compressed air.
13. Position the new gaskets on the intake manifold (see illustration). Note that the gaskets are equipped with installation tabs that must snap into place on the intake manifold. The words «Manifold Side» may appear on the gasket. If so, this will ensure proper installation. Make sure the gaskets snap into place and all intake port openings align.
7.13 Align the tabs on the intake gaskets with the tabs on the manifold and snap the gasket into place
14. Carefully set the manifold in place.
15. Install the bolts and tighten them following the recommended sequence (see illustrations) to the torque listed in this Chapter’s Specifications. Do not overtighten the bolts or gasket leaks may develop.
7.15a Intake manifold bolt tightening sequence — 5.3L and 6.2L engines
7.15b Intake manifold bolt tightening sequence — 6.0L engine
16. The remainder of installation is the reverse of removal. Start the engine and check carefully for vacuum leaks at the intake manifold joints.