Avalanche, Sierra, Silverado, C&K Series, 1999-2005

Intake Manifold 3

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Removal & Installation



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

     



    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. On 2002-04 models, 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: 44 inch lbs. (5 Nm). Check the manifold joints for shifting and fix as necessary.
    4.  
    5. 3rd pass: 89 inch lbs. (10 Nm).
    6.  
    7. 4th pass: 106 inch lbs. (12 Nm).
    8.  

  6.  
  7. On 2005-05 models, 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 engine

    8.  

  8.  
  9. Install the remaining components in the reverse order of the removal procedure.
  10.  
  11. Fill the cooling system, then connect the negative battery cable
  12.  
  13. Start the vehicle and verify that there are no leaks.
  14.  


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
     
    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 electrical connector
     
    Ignition coil electrical connector
     
    Engine Coolant Temperature (ECT) sensor electrical connector
     
    Engine harness bolt and studs
     
    CPA retainer from the ignition coil harness
     
    Alternator, injector harness and ignition coil harness connectors
     
    Throttle Position (TP) sensor connector
     
    Electronic Throttle Control (ETC) and purge valve solenoid connectors
     

  4.  
  5. Reposition the engine harness to the driver-s 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
     
    Unclip the EVAP tube from the fuel rail
     
    EVAP tube from the vent pipe at rear of engine
     
    EVAP tube
     
    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
     

  6.  

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

     



    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

    On 2002-04 models, tighten the bolts in the sequence shown, in 4 passes:
     

    1. 1st pass: 44 inch lbs. (5 Nm).
    2.  
    3. 2nd pass: 44 inch lbs. (5 Nm). Check the manifold joints for shifting and fix as necessary.
    4.  
    5. 3rd pass: 89 inch lbs. (10 Nm).
    6.  
    7. 4th pass: 106 inch lbs. (12 Nm).

      On 2005-06 models, tighten the bolts in the sequence shown, in 4 passes:
       

    8.  
    9. 1st pass: 44 inch lbs. (5 Nm)
    10.  
    11. 2nd pass: 71 inch lbs. (8 Nm). Check the manifold joints for shifting and fix as necessary.
    12.  
    13. 3rd pass: 106 inch lbs. (12 Nm).
    14.  
    15. 4th pass: 11 ft. lbs. (15 Nm).

      Click image to see an enlarged view

      Fig. Intake manifold bolt tightening sequence-8.1L engine

    16.  

  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.  


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. Before servicing the vehicle, refer to the precautions in the beginning of this section.
  2.  
  3. Relieve the fuel system pressure and drain the cooling system.
  4.  
  5. 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
     

  6.  
  7. 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, ignition coil and Engine Coolant Temperature (ECT) sensor electrical connectors
     
    Engine harness bolt and studs
     
    CPA retainer from the ignition coil harness
     
    Alternator, injector harness and ignition coil harness connectors
     
    Throttle Position (TP) sensor, Electronic Throttle Control (ETC) and purge valve solenoid connectors
     

  8.  
  9. Reposition the engine harness to the drivers side of the engine compartment.

    Bypass valve vacuum hose from the intake manifold
     
    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
     
    AIR pipe bolts from the exhaust manifold
     
    AIR pipe from the AIR pump pipe
     
    AIR pipe gasket and discard
     
    AIR pipe nut from the fuel rail stud
     
    AIR pipe bolts from the exhaust manifold
     
    AIR pipe from the AIR pump pipe
     
    AIR pipe gasket
     

  10.  
  11. Reposition the AIR pump hose clamp, then remove the air pump hose from the pump pipe.
    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.



    AIR pump pipe bolt from the cylinder head
     
    AIR pump pipe
     
    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
     

  12.  

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

     



    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: 44 inch lbs. (5 Nm). Check the manifold joints for shifting and fix as necessary.
    4.  
    5. 3rd pass: 89 inch lbs. (10 Nm)
    6.  
    7. 4th pass: 106 inch lbs. (12 Nm)

      Click image to see an enlarged view

      Fig. Intake manifold bolt tightening sequence-8.1L engine

    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.  


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. Before servicing the vehicle, refer to the precautions in the beginning of this section.
  2.  
  3. Relieve the fuel system pressure and drain the cooling system.
  4.  
  5. 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
     

  6.  
  7. 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, ignition coil and Engine Coolant Temperature (ECT) sensor electrical connectors
     
    Engine harness bolt and studs
     
    CPA retainer from the ignition coil harness
     
    Alternator, injector harness and ignition coil harness connectors
     
    Throttle Position (TP) sensor, Electronic Throttle Control (ETC) and purge valve solenoid connectors
     

  8.  
  9. Reposition the engine harness to the drivers side of the engine compartment.

    Bypass valve vacuum hose from the intake manifold
     
    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
     
    AIR pipe bolts from the exhaust manifold
     
    AIR pipe from the AIR pump pipe
     
    AIR pipe gasket and discard
     
    AIR pipe nut from the fuel rail stud
     
    AIR pipe bolts from the exhaust manifold
     
    AIR pipe from the AIR pump pipe
     
    AIR pipe gasket
     

  10.  
  11. Reposition the AIR pump hose clamp, then remove the air pump hose from the pump pipe.
    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.



    AIR pump pipe bolt from the cylinder head
     
    AIR pump pipe
     
    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
     

  12.  

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

     



    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: 44 inch lbs. (5 Nm). Check the manifold joints for shifting and fix as necessary.
    4.  
    5. 3rd pass: 89 inch lbs. (10 Nm)
    6.  
    7. 4th pass: 106 inch lbs. (12 Nm)

      Click image to see an enlarged view

      Fig. Intake manifold bolt tightening sequence-8.1L engine

    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.  


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.  


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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