Intake Manifold: Service and Repair

1. Relieve fuel system pressure as outlined under ``Fuel System Pressure Relief.''
2. Disconnect battery ground cable from battery.
3. Disconnect air bypass valve, throttle position sensor and EVP sensor electrical connectors.
4. Disconnect vacuum lines from EGR valve and manifold vacuum tree, then remove Sealed Housing Evaporative Determination system (SHED) EVAP lines from throttle body and electronic purge, if equipped.
5. Disconnect PCV hose, then remove throttle linkage shield.
6. Disconnect throttle linkage and speed control cables, then remove accelerator cable from bracket and position out of way.
7. Disconnect air inlet hoses from throttle body, then remove tube between EGR valve and rear exhaust manifold.
8. Remove two nuts retaining thermactor tube assembly, then one nut retaining thermactor bypass valve bracket to lower intake manifold.
9. On E-Series, remove nut retaining transmission filler tube, then remove tube bracket from manifold stud.
10. On all models, remove seven upper intake manifold retaining studs.
11. Remove screw and washer assembly retaining support bracket to manifold.
12. Remove upper intake manifold and throttle body as an assembly.
13. Disconnect inlet pipe from exhaust manifolds.
14. Disconnect power brake vacuum line, if equipped.
15. Remove bolts retaining manifolds to cylinder head, then lift the manifolds from the engine as an assembly.
16. Remove and discard gaskets.
17. Reverse procedure to install, noting the following:
a. Torque upper intake manifold retaining studs to 12-18 ft. lbs.

Fig. 12 Intake & exhaust manifold tightening sequence:

b. Tighten lower intake manifold attaching bolts and nuts to specifications in sequence shown in Fig. 12. The following manifold installation procedure should be used to extend exhaust manifold service life.
c. Clean cylinder head and manifold mating surfaces.
d. Remove tube fittings from original manifold and install in replacement manifold, as needed.
e. Apply suitable graphite grease to exhaust manifold to intake manifold mating surfaces.
f. Install 2 new bolts (part No. 374047-S) and a new stud (part No. 381733-S) into intake manifold.
g. Assemble intake manifold to exhaust manifold using lock washers and nuts. Tighten nuts finger tight only at this time.
h. Install a new intake manifold gasket. Do not install a combination intake/exhaust manifold gasket on a new exhaust manifold.
i. Apply suitable graphite grease to cylinder head-to-manifold mating surfaces.
j. Position manifold assemblies against cylinder head, ensuring intake manifold gaskets have not moved.
k. Install manifold attaching bolts and nuts and tighten to specifications in sequence shown in Fig. 12.
l. Tighten intake manifold to exhaust manifold retaining nuts to specifications.
m. Position a new gasket on exhaust pipe, then connect pipe to manifold and tighten retaining bolts to specifications.