Sierra, Silverado 2006-2007

Intake Manifold

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Removal & Installation



4.3L Engines
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Relieve the fuel system pressure
  4.  
  5. Remove or disconnect the following:

    Negative battery cable
     
    Air intake duct
     
    Wiring harness connectors and brackets from the manifold
     
    Throttle linkage and bracket from the upper manifold
     
    Cruise control cable, if equipped
     
    Fuel lines at the rear of the lower intake manifold
     
    Brake booster vacuum hose from the upper intake manifold
     
    Ignition coil and bracket
     
    Purge solenoid and bracket
     
    Studs and intake manifold attaching bolts, mark for reassembly
     
    Upper intake manifold
     
    Distributor housing and rotor, mark for reassembly
     
    Upper radiator hose from the thermostat housing
     
    Heater hoses and the bypass hose from the lower intake manifold
     
    Exhaust Gas Recirculation (EGR) valve
     
    Transmission dipstick tube, if equipped
     
    Positive Crankcase Ventilation (PCV) valve and hoses
     
    Air conditioning compressor and bracket. Without disconnecting, position aside
     
    Alternator bracket and bolt next to the thermostat housing, if needed
     
    Lower intake manifold mounting bolts and the lower manifold
     

  6.  

To install:

  1. Clean all gasket mating surfaces thoroughly.
  2.  
  3. Position the new gaskets on the cylinder heads with the port blocking plates at the rear and the words THIS SIDE UP facing up.
  4.  
  5. Apply a 3 / 16 inch (5mm) bead of RTV to the front and rear sealing surfaces on the engine block. Extend the bead 1 / 2 inch (13mm) up each cylinder head to retain the gasket.
  6.  
  7. Carefully position the lower intake manifold onto the engine.
  8.  
  9. Apply GM 1052080 or equivalent sealer to the lower intake manifold bolts
  10.  
  11. Torque the bolts using 3 steps in the sequence shown:
    1. Step 1: 27 inch lbs. (3 Nm).
    2.  
    3. Step 2: 106 inch lbs. (12 Nm).
    4.  
    5. Step 3: 11 ft. lbs. (15 Nm).

      Click image to see an enlarged view

      Fig. Lower intake manifold bolt tightening sequence-4.3L engines

    6.  

  12.  
  13. Install or connect the following:

    Alternator bracket and bolts near the thermostat housing, if removed
     
    Air conditioning compressor
     
    PCV valve and hose
     
    Transmission dipstick tube, if equipped
     
    EGR valve
     
    Upper radiator and bypass hose to the thermostat housing
     
    Distributor.
     

  14.  
  15. Position the upper intake manifold gasket on the lower manifold.
    WARNING
    Be careful not to pinch the injector tubes between the upper and lower manifolds.



    Upper intake manifold. Torque the bolts and studs to 88 inch lbs. (10 Nm).
     
    Purge control bracket and valve
     
    Ignition coil
     
    Brake booster vacuum
     
    Fuel lines
     
    Accelerator cable
     
    Cruise control cable, if equipped
     
    Wiring harness brackets and connections
     
    Air intake duct
     
    Negative battery cable
     

  16.  
  17. Refill and bleed the cooling system.
  18.  
  19. Pressurize the fuel system and check for leaks.
  20.  

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.

  1. 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.

    Click image to see an enlarged view

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

     

  2.  
  3. Clean the intake manifold in solvent.
  4.  
  5. Dry the intake manifold with compressed air.
  6.  
  7. Inspect the intake manifold vacuum passages for debris or restrictions.
  8.  
  9. Inspect for damaged or broken vacuum fittings, damaged MAP sensor mounting bore, or broken MAP sensor retaining tabs.
  10.  
  11. Inspect the composite intake manifold assembly for cracks or other damage.
  12.  
  13. Inspect the areas between the intake runners. Inspect all the gasket sealing surfaces for damage.
  14.  
  15. Inspect the fuel injector bores for excessive scoring or damage. Inspect the intake manifold cylinder head deck for warpage.
  16.  
  17. Locate a straight edge across the intake manifold cylinder head deck surface. Position the straight edge across a minimum of two runner port openings.
  18.  
  19. 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.
  20.  

To install:

  1. 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
     

  2.  
  3. 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).

    Click image to see an enlarged view

    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
     

  4.  

6.6L Engine
Center Manifold
  1. Remove the Exhaust Gas Recirculation (EGR) valve cooler tube.
  2.  
  3. Remove the intake manifold tube.
  4.  
  5. Remove and discard the 2 intake manifold tube gaskets.
  6.  
  7. Remove the turbocharger.
  8.  
  9. Remove the center intake manifold bolts/nuts.
  10.  
  11. Pull-up the center intake manifold in order to remove.
  12.  
  13. Remove and discard the gaskets.
  14.  
  15. Clean the center intake manifold in cleaning solvent and air dry.
  16.  

To install:

Click image to see an enlarged view

Fig. Center intake manifold-6.6L engines

  1. Install new center intake manifold gaskets.
  2.  
  3. Install the center intake manifold.
  4.  
  5. Install the center intake manifold bolts/nuts and tighten to 89 inch lbs. (10 Nm).
  6.  
  7. Install the turbocharger.
  8.  
  9. Install 2 new O-rings onto the intake manifold tube.
  10.  
  11. Lubricate the O-rings with clean engine oil to aid in the installation.
  12.  
  13. Install the intake manifold tube.
  14.  
  15. Install the EGR valve cooler tube.
  16.  

Left & Right Manifolds
  1. Drain the cooling system.
  2.  
  3. Remove or disconnect the following:
    NOTE
    The intake manifold uses sealer. If necessary, pry at the area by the common rail bolt holes and be careful to avoid damaging the sealing surfaces.



    Batteries cables
     
    Center intake manifold
     
    Fuel junction block
     
    Left or right fuel rail
     
    Intake manifold tube
     
    9 bolts and 2 nuts from the intake manifold. A bolt is located in the manifold opening.
     



    Intake manifold from the head. Cover the head openings to prevent debris from entering.
     

  4.  
  5. Clean all gaskets surface.
  6.  

To install:

  1. Install or connect the following:
    NOTE
    The left and right side manifolds are NOT interchangeable.



    A 1 / 8 in. (2-3mm) wide to 1 / 16 in (0.5-1.5mm) high bead of sealant to the sealing surface of the intake manifold
     



    Intake manifold
     
    Bolts and nuts. Tighten to 15 ft. lbs. (20 Nm), in sequence.

    Click image to see an enlarged view

    Fig. Left side intake manifold bolt tightening sequence-6.6L engines



    Click image to see an enlarged view

    Fig. Right side intake manifold bolt tightening sequence-6.6L engines

     
    Intake manifold tube
     
    Fuel rail
     
    Fuel junction block
     
    Turbocharger
     
    Negative battery cables
     

  2.  
  3. Fill cooling system.
  4.  

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.

  1. Relieve the fuel system pressure and drain the cooling system.
  2.  
  3. 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
     

  4.  
  5. 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
     

  6.  
  7. 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
     

  8.  

To install:

  1. Clean all gasket surfaces completely.
  2.  
  3. 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.

    Click image to see an enlarged view

    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
     

  4.  
  5. Install the intake manifold bolts and tighten, in the sequence shown, in 4 passes:
    1. 1st pass: 44 inch lbs. (5 Nm).
    2.  
    3. 2nd pass: 71 inch lbs. (8 Nm). Check the manifold joints for shifting and fix as necessary.
    4.  
    5. 3rd pass: 106 inch lbs. (12 Nm).
    6.  
    7. 4th pass: 11 ft. lbs. (15 Nm).

      Click image to see an enlarged view

      Fig. Intake manifold bolt tightening sequence-8.1L engines

    8.  

  6.  
  7. Install the remaining components in the reverse order of the removal procedure.
  8.  
  9. Fill the cooling system, then connect the negative battery cable
  10.  
  11. Start the vehicle and verify that there are no leaks.
  12.  

 
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