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

Timing Chain Cover, Chain, Sprockets, & Seal 2

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Removal & Installation



8.1L Engine

NOTE
This procedure requires the use of Crankshaft Sprocket Installer tool No. J 22102 and Crankshaft Protector Button tool No. J 42846.

  1. Drain the cooling system.
  2.  
  3. Remove or disconnect the following:
    NOTE
    The front cover gasket can be reused if it is not damaged.



    Negative battery cable
     
    Water pump
     
    Crankshaft balancer from the crankshaft
     
    Camshaft Position (CMP) sensor connector
     
    Engine harness clips from the battery cable channel
     
    CMP sensor bolt and sensor
     
    Battery cable channel bolt
     
    Battery cable channel and reposition
     
    Front cover bolts, front cover and gasket
     



    Crankshaft front oil seal from the front cover
     

  4.  
  5. Align the timing marks on the camshaft and crankshaft sprockets.

    Camshaft sprocket bolts
     
    Camshaft sprocket and timing chain
     

  6.  
  7. Install Crankshaft Protector Button tool No. J 42846 into the end of the crankshaft and remove the crankshaft sprocket using a 3-jawed puller.
  8.  
  9. Clean and inspect the timing chain and sprockets.
  10.  

To install:

  1. Use the Crankshaft Sprocket Installer tool No. J 22102 to install the crankshaft sprocket. Align the keyway of the sprocket with the crankshaft pin.
  2.  
  3. Remove the installation tool.
  4.  
  5. Rotate the crankshaft until the crankshaft sprocket alignment mark is in the 12 o-clock position.
  6.  
  7. Install the camshaft sprocket and timing chain, noting the following important points:
    1. The cam sprocket must be installed with the alignment mark at the 6 o-clock position.
    2.  
    3. The sprocket teeth must mesh with the timing chain to avoid damaging the camshaft retainer.
    4.  
    5. Never use a hammer to install the sprocket onto the camshaft.
    6.  

  8.  
  9. Make sure the crankshaft sprocket is alignment at the 12 o-clock position and the cam sprocket is at the 6 o-clock position.
  10.  
  11. Install the camshaft sprocket bolts and tighten, in two passes, to 22 ft. lbs. (30 Nm)
  12.  
  13. Use clean engine oil to lubricate the sealing surfaces of the front oil seal.
  14.  
  15. Install or connect the following:
    NOTE
    The front cover must be installed while the sealant is still wet to the touch.



    New seal into the front cover, using a suitable seal installation tool
     



    Sealant to the 2 places on the engine block where the front cover meets the oil pan
     
    Front cover gasket into the cover
     

  16.  
  17. Install the front cover, referring to the accompanying figure and using the following steps only:
    1. Hold the front cover (1) up to the crankshaft (2).
    2.  
    3. Lift the cover (1) while sliding the cover over the crankshaft (2).
    4.  
    5. Slide the front cover toward the engine block (5) while keeping the cover raised.
    6.  
    7. Lower the cover down over the dowel pin (4), allowing the front cover to rest on the sealant (3).

      Click image to see an enlarged view

      Fig. Proper front cover installation sequence-8.1L engine

    8.  

  18.  
  19. Install the front cover bolts and tighten, in sequence, as follows:
    1. 1st pass: 53 inch lbs. (6 Nm)
    2.  
    3. 2nd pass: 106 inch lbs. (12 Nm)

      Click image to see an enlarged view

      Fig. Engine front cover bolt tightening sequence-8.1L engine

    4.  

  20.  
  21. Install or connect the following:

    Battery cable channel and bolt. Tighten to 80 inch lbs. (9 Nm).
     
    CMP sensor. Inspect the O-ring first, replace if necessary and coat with oil before installation
     
    CMP sensor bolt to 106 inch lbs. (12 Nm)
     
    Engine harness clips to the battery cable channel
     
    CMP sensor electrical connector
     
    Crankshaft balancer
     
    Water pump
     
    Negative battery cable.
     

  22.  
  23. Fill the cooling system with the proper type and quantity of antifreeze.
  24.  


NOTE
This procedure requires the use of Crankshaft Sprocket Installer tool No. J 22102 and Crankshaft Protector Button tool No. J 42846.

  1. Before servicing the vehicle, refer to the precautions in the beginning of this section.
  2.  
  3. Drain the cooling system.
  4.  
  5. Remove or disconnect the following:
    NOTE
    The front cover gasket can be reused if it is not damaged.



    Negative battery cable
     
    Water pump
     
    Crankshaft balancer from the crankshaft
     
    Camshaft Position (CMP) sensor connector
     
    Engine harness clips from the battery cable channel
     
    CMP sensor bolt and sensor
     
    Battery cable channel bolt
     
    Battery cable channel and reposition
     
    Front cover bolts, front cover and gasket
     



    Crankshaft front oil seal from the front cover
     

  6.  
  7. Align the timing marks on the camshaft and crankshaft sprockets.

    Camshaft sprocket bolts
     
    Camshaft sprocket and timing chain
     

  8.  
  9. Install Crankshaft Protector Button tool No. J 42846 into the end of the crankshaft and remove the crankshaft sprocket using a 3-jawed puller.
  10.  
  11. Clean and inspect the timing chain and sprockets.
  12.  

To install:

  1. Use the Crankshaft Sprocket Installer tool No. J 22102 to install the crankshaft sprocket. Align the keyway of the sprocket with the crankshaft pin.
  2.  
  3. Remove the installation tool.
  4.  
  5. Rotate the crankshaft until the crankshaft sprocket alignment mark is in the 12 o-clock position.
  6.  
  7. Install the camshaft sprocket and timing chain, noting the following important points:
    1. The cam sprocket must be installed with the alignment mark at the 6 o-clock position.
    2.  
    3. The sprocket teeth must mesh with the timing chain to avoid damaging the camshaft retainer.
    4.  
    5. Never use a hammer to install the sprocket onto the camshaft.
    6.  

  8.  
  9. Make sure the crankshaft sprocket is alignment at the 12 o-clock position and the cam sprocket is at the 6 o-clock position.
  10.  
  11. Install the camshaft sprocket bolts and tighten, in two passes, to 22 ft. lbs. (30 Nm)
  12.  
  13. Use clean engine oil to lubricate the sealing surfaces of the front oil seal.
  14.  
  15. Install or connect the following:
    NOTE
    The front cover must be installed while the sealant is still wet to the touch.



    New seal into the front cover, using a suitable seal installation tool
     



    Sealant to the 2 places on the engine block where the front cover meets the oil pan
     
    Front cover gasket into the cover
     

  16.  
  17. Install the front cover, referring to the accompanying figure and using the following steps only:
    1. Hold the front cover (1) up to the crankshaft (2).
    2.  
    3. Lift the cover (1) while sliding the cover over the crankshaft (2).
    4.  
    5. Slide the front cover toward the engine block (5) while keeping the cover raised.
    6.  
    7. Lower the cover down over the dowel pin (4), allowing the front cover to rest on the sealant (3).

      Click image to see an enlarged view

      Fig. Proper front cover installation sequence-8.1L engine

    8.  

  18.  
  19. Install the front cover bolts and tighten, in sequence, as follows:
    1. 1st pass: 53 inch lbs. (6 Nm).
    2.  
    3. 2nd pass: 106 inch lbs. (12 Nm).

      Click image to see an enlarged view

      Fig. Engine front cover bolt tightening sequence-8.1L engine

    4.  

  20.  
  21. Install or connect the following:

    Battery cable channel and bolt. Tighten to 80 inch lbs. (9 Nm)
     
    CMP sensor. Inspect the O-ring first, replace if necessary and coat with oil before installation
     
    CMP sensor bolt to 106 inch lbs. (12 Nm)
     
    Engine harness clips to the battery cable channel
     
    CMP sensor electrical connector
     
    Crankshaft balancer
     
    Water pump
     
    Negative battery cable.
     

  22.  
  23. Fill the cooling system with the proper type and quantity of antifreeze.
  24.  


NOTE
This procedure requires the use of Crankshaft Sprocket Installer tool No. J 22102 and Crankshaft Protector Button tool No. J 42846.

  1. Before servicing the vehicle, refer to the precautions in the beginning of this section.
  2.  
  3. Drain the cooling system.
  4.  
  5. Remove or disconnect the following:
    NOTE
    The front cover gasket can be reused if it is not damaged.



    Negative battery cable
     
    Water pump
     
    Crankshaft balancer from the crankshaft
     
    Camshaft Position (CMP) sensor connector
     
    Engine harness clips from the battery cable channel
     
    CMP sensor bolt and sensor
     
    Battery cable channel bolt
     
    Battery cable channel and reposition
     
    Front cover bolts, front cover and gasket
     



    Crankshaft front oil seal from the front cover
     

  6.  
  7. Align the timing marks on the camshaft and crankshaft sprockets.

    Camshaft sprocket bolts
     
    Camshaft sprocket and timing chain
     

  8.  
  9. Install Crankshaft Protector Button tool No. J 42846 into the end of the crankshaft and remove the crankshaft sprocket using a 3-jawed puller.
  10.  
  11. Clean and inspect the timing chain and sprockets.
  12.  

To install:

  1. Use the Crankshaft Sprocket Installer tool No. J 22102 to install the crankshaft sprocket. Align the keyway of the sprocket with the crankshaft pin.
  2.  
  3. Remove the installation tool.
  4.  
  5. Rotate the crankshaft until the crankshaft sprocket alignment mark is in the 12 o-clock position.
  6.  
  7. Install the camshaft sprocket and timing chain, noting the following important points:
    1. The cam sprocket must be installed with the alignment mark at the 6 o-clock position.
    2.  
    3. The sprocket teeth must mesh with the timing chain to avoid damaging the camshaft retainer.
    4.  
    5. Never use a hammer to install the sprocket onto the camshaft.
    6.  

  8.  
  9. Make sure the crankshaft sprocket is alignment at the 12 o-clock position and the cam sprocket is at the 6 o-clock position.
  10.  
  11. Install the camshaft sprocket bolts and tighten, in two passes, to 22 ft. lbs. (30 Nm)
  12.  
  13. Use clean engine oil to lubricate the sealing surfaces of the front oil seal.
  14.  
  15. Install or connect the following:
    NOTE
    The front cover must be installed while the sealant is still wet to the touch.



    New seal into the front cover, using a suitable seal installation tool
     



    Sealant to the 2 places on the engine block where the front cover meets the oil pan
     
    Front cover gasket into the cover
     

  16.  
  17. Install the front cover, referring to the accompanying figure and using the following steps only:
    1. Hold the front cover (1) up to the crankshaft (2).
    2.  
    3. Lift the cover (1) while sliding the cover over the crankshaft (2).
    4.  
    5. Slide the front cover toward the engine block (5) while keeping the cover raised.
    6.  
    7. Lower the cover down over the dowel pin (4), allowing the front cover to rest on the sealant (3).

      Click image to see an enlarged view

      Fig. Proper front cover installation sequence-8.1L engine

    8.  

  18.  
  19. Install the front cover bolts and tighten, in sequence, as follows:
    1. 1st pass: 53 inch lbs. (6 Nm).
    2.  
    3. 2nd pass: 106 inch lbs. (12 Nm).

      Click image to see an enlarged view

      Fig. Engine front cover bolt tightening sequence-8.1L engine

    4.  

  20.  
  21. Install or connect the following:

    Battery cable channel and bolt. Tighten to 80 inch lbs. (9 Nm)
     
    CMP sensor. Inspect the O-ring first, replace if necessary and coat with oil before installation
     
    CMP sensor bolt to 106 inch lbs. (12 Nm)
     
    Engine harness clips to the battery cable channel
     
    CMP sensor electrical connector
     
    Crankshaft balancer
     
    Water pump
     
    Negative battery cable.
     

  22.  
  23. Fill the cooling system with the proper type and quantity of antifreeze.
  24.  

 
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