Ford repair professionals: How to Replace Intake Manifold on GMC, Chevrolet and Cadillac models?

This chapter Provides details for replacing Intake Manifold.
The procedure covers Following car models Listed Below:-----
Cadillac Escalade, GMC Suburban 1500 & 2500, Chevrolet Tahoe, GMC Yukon, Yukon XL 1500 & 2500 (2006-2007), Yukon Denali and Yukon Denali XL (2005-2006).GMC Sierra, Chevrolet Silverado 2006-2007.

The procedure is mentioned for 8.1L engine AND
4.8L, 5.3L, 6.0L & 6.2L Engine Models.

The procedure is as follows:-----

Intake Manifold
REMOVAL & INSTALLATION
4.8L, 5.3L, 6.0L & 6.2L Engines

NOTE

The intake manifold, throttle body, fuel injection rail, and fuel injectors may be removed as an assembly. If not servicing the individual components, remove the manifold as a complete assembly.

Remove or disconnect the following:

Alternator

Positive Crankcase Ventilation (PCV) hose and valve

Manifold Absolute Pressure (MAP) sensor, if required

Engine coolant air bleed clamp and hose from the throttle body

Knock sensor connector, if required.

Accelerator control cable bracket and bolts, if required

Fuel rail with injectors, if required

EVAP solenoid, bolt, and isolator

Any additional engine harness attachment points and set aside

Intake manifold bolts

Intake manifold with gaskets

Intake manifold-to-cylinder head gaskets from the manifold. Discard the intake manifold gaskets.

Fig. Always use new gaskets-4.8L, 5.3L, 6.0L and 6.2L engines

Clean the intake manifold in solvent.

Dry the intake manifold with compressed air.

Inspect the intake manifold vacuum passages for debris or restrictions.

Inspect for damaged or broken vacuum fittings, damaged MAP sensor mounting bore, or broken MAP sensor retaining tabs.

Inspect the composite intake manifold assembly for cracks or other damage.

Inspect the areas between the intake runners. Inspect all the gasket sealing surfaces for damage.

Inspect the fuel injector bores for excessive scoring or damage. Inspect the intake manifold cylinder head deck for warpage.

Locate a straight edge across the intake manifold cylinder head deck surface. Position the straight edge across a minimum of two runner port openings.

Insert a feeler gauge between the intake manifold and the straight edge. A intake manifold with warpage in excess of 0.118 in. (3mm) over a 7.87 in. (200mm) area is warped and should be replaced.

To install:

Install or connect the following:

MAP sensor

EVAP solenoid, bolt, and isolator. Tighten the bolt to 89 inch lbs. (10 Nm).

NEW intake manifold-to-cylinder head gaskets

Intake manifold

Apply a 0.20 in. (5mm) band of threadlock GM P/N 12345382 or equivalent to the threads of the intake manifold bolts.

Intake manifold bolts. Tighten intake manifold bolts first pass in sequence to 44 inch lbs. (5 Nm). Tighten intake manifold bolts final pass in sequence to 89 inch lbs. (10 Nm).

Fig. Lower intake manifold bolt tightening sequence-4.8L, 5.3L, 6.0L and 6.2L engines
PCV valve and hose

Coolant air bleed hose and clamp onto the throttle body

Accelerator control cable bracket and bolts. Tighten the bolts to 89 inch lbs. (10 Nm).

Alternator

8.1L Engine

NOTE

The intake manifold, throttle body, fuel rail and injectors can be removed as an assembly. If you do not need to service these components individually, remove the manifold as a complete assembly.

Relieve the fuel system pressure and drain the cooling system.

Remove or disconnect the following:

Air cleaner outlet duct

Intake manifold sight shield

Fuel feed and return pipes

Engine harness clips from the studs on the front of the dash

Engine harness clip from the wheelhouse splash shield

Pressure cycling switch, surge tank switch and Mass Air Flow (MAF) electrical connectors

Reposition the engine harness to the top of the engine

Connector Position Assurance (CPA) retainer from the ignition coil harness

Manifold Absolute Pressure (MAP) sensor connector

Ignition coil connector(s)

Engine Coolant Temperature (ECT) sensor electrical connector

Engine harness bolt and studs

CPA retainer from the ignition coil harness

Alternator connector

Injector harness connector

Ignition coil harness connector

Throttle Position (TP) sensor connector

Electronic Throttle Control (ETC) connector

Purge valve solenoid connector

Reposition the engine harness to the drivers side of the engine compartment.

WARNING
Do NOT try to remove the intake manifold by prying under the sealing surfaces.

NOTE
The splash shield is reusable and secured using a snap-in fit. Do not distort the shield during removal.

Bypass valve vacuum hose from the intake manifold

EVAP tubes

Exhaust Gas Recirculation (EGR) valve electrical connector

EGR pipe bolts from the EGR adapter. Reposition the EGR pipe

EGR valve pipe gasket and discard

Secondary Air Injection (AIR) pipe nut from the fuel rail stud, if equipped

Fuel pressure regulator vacuum hose

Fuel rail studs and fuel rail, ONLY if replacing the manifold

Intake manifold bolts

Intake manifold

Intake manifold side gaskets and end seals and discard

Splash shield

To install:

Clean all gasket surfaces completely.

Install or connect the following:

NOTE
Make sure the manifold gasket tabs align with the hole in the head gasket.

Splash shield. Make sure the shield fits properly between the cylinder head.

Fig. Make sure that the splash shield snap fits between the cylinder heads-8.1L engines

New intake manifold end seals

New intake manifold side gaskets onto the heads. Make sure the stamped This Side Up is showing.

Intake manifold to the block

Apply a suitable thread locking material to at least 8 threads of the intake manifold bolts

Install the intake manifold bolts and tighten, in the sequence shown, in 4 passes:
1. 1st pass: 44 inch lbs. (5 Nm).
2. 2nd pass: 71 inch lbs. (8 Nm). Check the manifold joints for shifting and fix as necessary.
3. 3rd pass: 106 inch lbs. (12 Nm).
4. 4th pass: 11 ft. lbs. (15 Nm).
  
  Fig. Intake manifold bolt tightening sequence-8.1L engines