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

Timing Chain Cover, Chain, Sprockets, & Seal 1

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The manufacturer recommends that the front cover oil seal be replaced whenever the cover is removed.

The manufacturer recommends that the front cover oil seal be replaced whenever the cover is removed.

General Information



The manufacturer recommends that the front cover oil seal be replaced whenever the cover is removed.


NOTE
The manufacturer recommends that the front cover oil seal be replaced whenever the cover is removed.

Removal & Installation



4.3L, 5.0L, 5.7L & 7.4L Engines
  1. Drain the cooling system.
  2.  
  3. Remove or disconnect the following:
    NOTE
    If equipped with a composite front cover, it must be replaced with a new one. Reusing the front cover may result in oil leaks.



    Negative battery cable
     
    Fan shroud assembly
     
    Belts, pulleys and water pump assembly
     
    Crankshaft pulley and damper
     
    Oil pan-to-front cover bolts
     

  4.  
  5. Remove the engine shield bolts and shield.
  6.  
  7. Disconnect the Crankshaft Position (CKP) sensor electrical connector, if equipped.
  8.  
  9. Remove the CKP sensor and discard the o-ring.

    Screws holding the timing chain cover to the block
     
    Cover and gaskets.
     

  10.  
  11. Remove the crankshaft position (CKP) sensor reluctor ring, if equipped.
  12.  
  13. Use a suitable tool to pry the old seal out of the front face of the cover.
  14.  
  15. Rotate the crankshaft until the timing marks on the camshaft and crankshaft sprockets are in proper alignment. This will put no. 4 cylinder at TDC.
  16.  
  17. Unsnap the timing chain tensioner shoe from the pin.
  18.  
  19. Remove or disconnect the following:
    NOTE
    The camshaft sprocket (located by a dowel) is lightly pressed onto the camshaft and should come off easily. The chain comes off with the camshaft sprocket.



    Camshaft sprocket-to-camshaft nut and/or bolts
     
    Camshaft sprocket (along with the timing chain), if the sprocket is difficult to remove, use a plastic mallet to bump the sprocket from the camshaft.

    Click image to see an enlarged view

    Fig. Timing mark alignment for timing chain removal and installation-gasoline engines

     

  20.  
  21. If necessary use J-5825-A, or equivalent, crankshaft sprocket removal tool to free the timing sprocket from the crankshaft.
  22.  
  23. Remove the crankshaft balancer key.
  24.  
  25. If necessary, remove the timing chain tensioner bracket bolt and bracket.
  26.  

To install:

  1. Inspect the timing chain and the timing sprockets for wear or damage, replace the damaged parts as necessary.
  2.  
  3. Clean the gasket mounting surfaces of all remaining traces of old gasket.
    NOTE
    During installation, coat the thrust surfaces lightly with Molykote® or equivalent pre-lube.

  4.  
  5. If necessary, install the timing chain tensioner bracket and bolt and tighten to 106 inch lbs. (12 Nm).
  6.  
  7. Install the key into the crankshaft keyway. The crankshaft balancer key should be parallel to the crankshaft or with a slight incline.
  8.  
  9. Install or connect the following:

    Crankshaft sprocket onto the crankshaft, use tool J-5590, crankshaft sprocket installation tool, and a hammer, without disturbing the position of the engine.
     
    Timing chain, arrange the camshaft sprocket in such a way that the timing marks will align between the shaft centers and the camshaft locating dowel will enter the dowel hole in the cam sprocket.
     
    Cam sprocket, with the chain mounted under it in position on the front of the camshaft. Torque the camshaft sprocket-to-camshaft retainer bolts to 106 inch lbs. (12 Nm) on 5.0L and 5.7L, or 18 ft. lbs. (25 Nm) on 4.3L.
     

  10.  
  11. Install the timing chain tensioner shoe onto the bracket and position the top of the shoe under the tab at the top of the bracket.
  12.  
  13. With the timing chain installed, turn the crankshaft 2 complete revolutions, then check to make certain that the timing marks are in correct alignment between the shaft centers.
    NOTE
    Coat the lip of the new seal with oil prior to installation.



    New seal so that the open end is toward the inside of the cover, using seal driver J-22102
     
    New front pan seal, cutting the tabs off.
     

  14.  
  15. Coat a new cover gasket with adhesive sealer and position it on the block.
  16.  
  17. Apply a 1 / 8 in. (3mm) bead of RTV gasket material to the front cover.
  18.  
  19. Install the crankshaft position (CKP) sensor reluctor ring, if equipped.
  20.  
  21. Install the front cover carefully onto the locating dowels and tighten the attaching screws
  22.  
  23. Install the CKP sensor and new o-ring.
  24.  
  25. Connect the Crankshaft Position (CKP) sensor electrical connector, if equipped.
  26.  
  27. Install the engine shield bolts and shield.

    Oil pan, if removed
     
    Cover-to-pan bolts and tighten to 106 inch lbs. (12 Nm)
     
    Torsional damper
     
    Water pump assembly
     
    Negative battery cable
     

  28.  
  29. Fill the cooling system with the proper type and quantity of antifreeze.
  30.  

  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
    If equipped with a composite front cover, it must be replaced with a new one. Reusing the front cover may result in oil leaks.



    Negative battery cable
     
    Fan shroud assembly
     
    Belts, pulleys and water pump assembly
     
    Crankshaft pulley and damper
     
    Oil pan-to-front cover bolts
     



    Screws holding the timing chain cover to the block.
     
    Cover and gaskets.
     

  6.  
  7. Use a suitable tool to pry the old seal out of the front face of the cover.
  8.  
  9. Rotate the crankshaft until the timing marks on the camshaft and crankshaft sprockets are in proper alignment.
    NOTE
    The camshaft sprocket (located by a dowel) is lightly pressed onto the camshaft and should come off easily. The chain comes off with the camshaft sprocket.



    Camshaft sprocket-to-camshaft nut and/or bolts
     
    Camshaft sprocket (along with the timing chain), if the sprocket is difficult to remove, use a plastic mallet to bump the sprocket from the camshaft.

    Click image to see an enlarged view

    Fig. Timing mark alignment for timing chain removal and installation-gasoline engines

     

  10.  
  11. If necessary use J-5825-A, or equivalent, crankshaft sprocket removal tool to free the timing sprocket from the crankshaft.
  12.  

To install:

  1. Inspect the timing chain and the timing sprockets for wear or damage, replace the damaged parts as necessary.
  2.  
  3. Clean the gasket mounting surfaces of all remaining traces of old gasket.
    NOTE
    During installation, coat the thrust surfaces lightly with Molykote® or equivalent pre-lube.

  4.  
  5. Install or connect the following:

    Crankshaft sprocket onto the crankshaft, use tool J-5590, or equivalent, crankshaft sprocket installation tool, and a hammer, without disturbing the position of the engine.
     
    Timing chain, arrange the camshaft sprocket in such a way that the timing marks will align between the shaft centers and the camshaft locating dowel will enter the dowel hole in the cam sprocket.
     
    Cam sprocket, with the chain mounted under it in position on the front of the camshaft. Torque the camshaft sprocket-to-camshaft retainer bolts to 106 inch lbs. (12 Nm).
     

  6.  
  7. With the timing chain installed, turn the crankshaft 2 complete revolutions, then check to make certain that the timing marks are in correct alignment between the shaft centers.
    NOTE
    Coat the lip of the new seal with oil prior to installation.



    New seal so that the open end is toward the inside of the cover, Using seal driver J-22102, or equivalent.
     
    New front pan seal, cutting the tabs off.
     

  8.  
  9. Coat a new cover gasket with adhesive sealer and position it on the block.
  10.  
  11. Apply a 1 / 8 in. (3mm) bead of RTV gasket material to the front cover.

    Cover carefully onto the locating dowels and tighten the attaching screws
     
    Oil pan, if removed
     
    Cover-to-pan bolts, Torque to 106 inch lbs. (12 Nm).
     
    Torsional damper
     
    Water pump assembly
     
    Negative battery cable
     

  12.  
  13. Fill the cooling system with the proper type and quantity of antifreeze.
  14.  

  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
    If equipped with a composite front cover, it must be replaced with a new one. Reusing the front cover may result in oil leaks.



    Negative battery cable
     
    Fan shroud assembly
     
    Belts, pulleys and water pump assembly
     
    Crankshaft pulley and damper
     
    Oil pan-to-front cover bolts
     



    Screws holding the timing chain cover to the block.
     
    Cover and gaskets.
     

  6.  
  7. Use a suitable tool to pry the old seal out of the front face of the cover.
  8.  
  9. Rotate the crankshaft until the timing marks on the camshaft and crankshaft sprockets are in proper alignment.
    NOTE
    The camshaft sprocket (located by a dowel) is lightly pressed onto the camshaft and should come off easily. The chain comes off with the camshaft sprocket.



    Camshaft sprocket-to-camshaft nut and/or bolts
     
    Camshaft sprocket (along with the timing chain), if the sprocket is difficult to remove, use a plastic mallet to bump the sprocket from the camshaft.

    Click image to see an enlarged view

    Fig. Timing mark alignment for timing chain removal and installation-gasoline engines

     

  10.  
  11. If necessary use J-5825-A, or equivalent, crankshaft sprocket removal tool to free the timing sprocket from the crankshaft.
  12.  

To install:

  1. Inspect the timing chain and the timing sprockets for wear or damage, replace the damaged parts as necessary.
  2.  
  3. Clean the gasket mounting surfaces of all remaining traces of old gasket.
    NOTE
    During installation, coat the thrust surfaces lightly with Molykote® or equivalent pre-lube.

  4.  
  5. Install or connect the following:

    Crankshaft sprocket onto the crankshaft, use tool J-5590, or equivalent, crankshaft sprocket installation tool, and a hammer, without disturbing the position of the engine.
     
    Timing chain, arrange the camshaft sprocket in such a way that the timing marks will align between the shaft centers and the camshaft locating dowel will enter the dowel hole in the cam sprocket.
     
    Cam sprocket, with the chain mounted under it in position on the front of the camshaft. Torque the camshaft sprocket-to-camshaft retainer bolts to 106 inch lbs. (12 Nm).
     

  6.  
  7. With the timing chain installed, turn the crankshaft 2 complete revolutions, then check to make certain that the timing marks are in correct alignment between the shaft centers.
    NOTE
    Coat the lip of the new seal with oil prior to installation.



    New seal so that the open end is toward the inside of the cover, Using seal driver J-22102, or equivalent.
     
    New front pan seal, cutting the tabs off.
     

  8.  
  9. Coat a new cover gasket with adhesive sealer and position it on the block.
  10.  
  11. Apply a 1 / 8 in. (3mm) bead of RTV gasket material to the front cover.

    Cover carefully onto the locating dowels and tighten the attaching screws
     
    Oil pan, if removed
     
    Cover-to-pan bolts, Torque to 106 inch lbs. (12 Nm).
     
    Torsional damper
     
    Water pump assembly
     
    Negative battery cable
     

  12.  
  13. Fill the cooling system with the proper type and quantity of antifreeze.
  14.  

4.8L, 5.3L & 6.0L Engine
  1. Drain the cooling system.
  2.  
  3. Remove or disconnect the following:

    Click image to see an enlarged view

    Fig. Front cover and gasket-4.8L, 5.3L and 6.0L engines



    Negative battery cable
     
    Water pump
     
    Crankshaft balancer from the crankshaft
     
    Front cover bolts
     
    Front cover and gasket. Discard the front cover gasket.
     
    Crankshaft front oil seal from the cover
     
    Oil pump
     

  4.  
  5. Rotate the crankshaft until the timing marks on the crankshaft and the camshaft sprockets are aligned.
    NOTE
    Do not turn the crankshaft assembly after the timing chain has been removed in order to prevent damage to the piston assemblies or the valves.

  6.  
  7. Remove or disconnect the following:

    Click image to see an enlarged view

    Fig. Sprocket and chain removal-4.8L, 5.3L and 6.0L engines



    Camshaft sprocket bolts
     
    Camshaft sprocket and timing chain
     
    Crankshaft sprocket
     
    Crankshaft sprocket key
     

  8.  

To install:

Click image to see an enlarged view

Fig. Crankshaft sprocket installation-4.8L, 5.3L and 6.0L engines

  1. Install or connect the following:
    NOTE
    Do not lubricate the oil seal sealing surface.



    Key into the crankshaft keyway
     
    Crankshaft sprocket onto the front of the crankshaft. Align the crankshaft key with the crankshaft sprocket keyway. Rotate the crankshaft sprocket until the alignment mark is in the 12 o'clock position.
     
    Camshaft sprocket and timing chain. Locate the camshaft sprocket alignment mark in the 6 o'clock position.
     
    Camshaft sprocket bolts and tighten to 26 ft. lbs. (35 Nm)

    Click image to see an enlarged view

    Fig. Timing mark alignment-4.8L, 5.3L and 6.0L engines

     

  2.  
  3. Lubricate the outer edge of the oil seal with clean engine oil. Lubricate the front cover oil seal bore with clean engine oil.
  4.  
  5. Install the crankshaft front oil seal with an installer.
    NOTE
    Do not apply any type of sealant to the front cover gasket (unless specified). Special tools are used to properly align the engine front cover at the oil pan surface and to center the crankshaft front oil seal.

  6.  
  7. Install the front cover gasket, cover, and bolts onto the engine. Tighten the cover bolts finger-tight. Do not over tighten.

    Click image to see an enlarged view

    Fig. J41480 installation-4.8L, 5.3L and 6.0L engines

  8.  
  9. Start the J41480 tool-to-front cover bolts. Don-t tighten the bolts yet.
    NOTE
    Align the tapered legs of the tool with the machined alignment surfaces on the front cover.



    Click image to see an enlarged view

    Fig. Seal alignment tool installation-4.8L, 5.3L and 6.0L engines

  10.  
  11. Install tool J41476 . Install the crankshaft balancer bolt. Tighten the crankshaft balancer bolt by hand until snug. Do not over tighten. Tighten the J41480 bolts and front cover bolts to 18 ft. lbs. (25 Nm).
  12.  
  13. Remove the tools.
  14.  
  15. Install the used crankshaft balancer bolt and tighten to 240 ft. lbs. (330 Nm).
  16.  
  17. Remove the used bolt.
    NOTE
    The nose of the crankshaft should be recessed 0.094-0.176 in (2.4-4.48 mm) into the balancer bore.

  18.  
  19. Install a NEW crankshaft balancer bolt and tighten to 37 ft. lbs. (50 Nm), then tighten an additional 140 degrees.
  20.  
  21. Place a straight edge across the engine block and front cover oil pan sealing surfaces. Avoid contact with the portion of the gasket that protrudes into the oil pan surface. Insert a feeler gauge between the front cover and the straight edge tool. The cover must be flush with the oil pan surface or no more than 0.02 in. (0.5mm) below flush. If the front cover-to-engine block oil pan surface alignment is not within specifications, repeat the cover alignment procedure. If the correct front cover-to-engine block alignment cannot be obtained, replace the front cover.
  22.  
  23. Install the crankshaft balancer bolt. Tighten the crankshaft balancer bolt by hand until snug. Do not over tighten the bolt.
  24.  
  25. Snug the oil pan-to-cover bolts in order to position the cover at the pan rail.
  26.  
  27. Tighten the oil pan-to-front cover bolts to 18 ft. lbs. (25 Nm).
  28.  
  29. Tighten the front cover bolts to 18 ft. lbs. (25 Nm).
  30.  
  31. Install the water pump.
  32.  

  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:

    Negative battery cable
     
    Water pump
     
    Crankshaft balancer from the crankshaft
     
    Front cover bolts

    Click image to see an enlarged view

    Fig. Front cover and gasket-4.8L, 5.3L, 6.0L

     
    Front cover and gasket. Discard the front cover gasket.
     
    Crankshaft front oil seal from the cover
     
    Oil pump
     

  6.  
  7. Rotate the crankshaft until the timing marks on the crankshaft and the camshaft sprockets are aligned.
    NOTE
    Do not turn the crankshaft assembly after the timing chain has been removed in order to prevent damage to the piston assemblies or the valves.

  8.  
  9. Remove or disconnect the following:



    Click image to see an enlarged view

    Fig. Sprocket and chain removal-4.8L, 5.3L, 6.0L

    Camshaft sprocket bolts
     
    Camshaft sprocket and timing chain
     
    Crankshaft sprocket
     
    Crankshaft sprocket key
     

  10.  

To install:

  1. Install or connect the following:
    NOTE
    Do not lubricate the oil seal sealing surface.



    Key into the crankshaft keyway

    Click image to see an enlarged view

    Fig. Crankshaft sprocket installation-4.8L, 5.3L, 6.0L

     
    Crankshaft sprocket onto the front of the crankshaft. Align the crankshaft key with the crankshaft sprocket keyway. Rotate the crankshaft sprocket until the alignment mark is in the 12 o'clock position.

    Click image to see an enlarged view

    Fig. Timing mark alignment-4.8L, 5.3L, 6.0L

     
    Camshaft sprocket and timing chain. Locate the camshaft sprocket alignment mark in the 6 o'clock position.
     
    Camshaft sprocket bolts. Tighten the camshaft sprocket bolts to 26 ft. lbs. (35 Nm).
     

  2.  
  3. Lubricate the outer edge of the oil seal with clean engine oil. Lubricate the front cover oil seal bore with clean engine oil.
  4.  
  5. Install the crankshaft front oil seal with an installer.
    NOTE
    Do not apply any type sealant to the front cover gasket (unless specified). Special tools are used to properly align the engine front cover at the oil pan surface and to center the crankshaft front oil seal.

  6.  
  7. Install the front cover gasket, cover, and bolts onto the engine. Tighten the cover bolts finger tight. Do not overtighten.

    Click image to see an enlarged view

    Fig. J41480 installation-4.8L, 5.3L, 6.0L

  8.  
  9. Start the J41480 tool-to-front cover bolts. Don-t tighten the bolts yet.
    NOTE
    Align the tapered legs of the tool with the machined alignment surfaces on the front cover.



    Click image to see an enlarged view

    Fig. Seal alignment tool installation-4.8L, 5.3L, 6.0L

  10.  
  11. Install tool J41476 . Install the crankshaft balancer bolt. Tighten the crankshaft balancer bolt by hand until snug. Do not overtighten. Tighten the J41480 bolts and front cover bolts to 25 Nm (18 ft. lbs.).
  12.  
  13. Remove the tools.
  14.  
  15. Place a straight edge across the engine block and front cover oil pan sealing surfaces. Avoid contact with the portion of the gasket that protrudes into the oil pan surface. Insert a feeler gauge between the front cover and the straight edge tool. The cover must be flush with the oil pan surface or no more than 0.5 mm (0.02 in) below flush. If the front cover-to-engine block oil pan surface alignment is not within specifications, repeat the cover alignment procedure. If the correct front cover-to-engine block alignment cannot be obtained, replace the front cover.
  16.  
  17. Install the crankshaft balancer bolt. Tighten the crankshaft balancer bolt by hand until snug. Do not overtighten the bolt.
  18.  
  19. Snug the oil pan-to-cover bolts in order to position the cover at the pan rail.
  20.  
  21. Tighten the oil pan-to-front cover bolts to 25 Nm (18 ft. lbs.).
  22.  
  23. Tighten the front cover bolts to 25 Nm (18 ft. lbs.).
  24.  
  25. Install the water pump.
  26.  

  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:

    Negative battery cable
     
    Water pump
     
    Crankshaft balancer from the crankshaft
     
    Front cover bolts

    Click image to see an enlarged view

    Fig. Front cover and gasket-4.8L, 5.3L, 6.0L

     
    Front cover and gasket. Discard the front cover gasket.
     
    Crankshaft front oil seal from the cover
     
    Oil pump
     

  6.  
  7. Rotate the crankshaft until the timing marks on the crankshaft and the camshaft sprockets are aligned.
    NOTE
    Do not turn the crankshaft assembly after the timing chain has been removed in order to prevent damage to the piston assemblies or the valves.

  8.  
  9. Remove or disconnect the following:



    Click image to see an enlarged view

    Fig. Sprocket and chain removal-4.8L, 5.3L, 6.0L

    Camshaft sprocket bolts
     
    Camshaft sprocket and timing chain
     
    Crankshaft sprocket
     
    Crankshaft sprocket key
     

  10.  

To install:

  1. Install or connect the following:
    NOTE
    Do not lubricate the oil seal sealing surface.



    Key into the crankshaft keyway

    Click image to see an enlarged view

    Fig. Crankshaft sprocket installation-4.8L, 5.3L, 6.0L

     
    Crankshaft sprocket onto the front of the crankshaft. Align the crankshaft key with the crankshaft sprocket keyway. Rotate the crankshaft sprocket until the alignment mark is in the 12 o'clock position.

    Click image to see an enlarged view

    Fig. Timing mark alignment-4.8L, 5.3L, 6.0L

     
    Camshaft sprocket and timing chain. Locate the camshaft sprocket alignment mark in the 6 o'clock position.
     
    Camshaft sprocket bolts. Tighten the camshaft sprocket bolts to 26 ft. lbs. (35 Nm).
     

  2.  
  3. Lubricate the outer edge of the oil seal with clean engine oil. Lubricate the front cover oil seal bore with clean engine oil.
  4.  
  5. Install the crankshaft front oil seal with an installer.
    NOTE
    Do not apply any type sealant to the front cover gasket (unless specified). Special tools are used to properly align the engine front cover at the oil pan surface and to center the crankshaft front oil seal.

  6.  
  7. Install the front cover gasket, cover, and bolts onto the engine. Tighten the cover bolts finger tight. Do not overtighten.

    Click image to see an enlarged view

    Fig. J41480 installation-4.8L, 5.3L, 6.0L

  8.  
  9. Start the J41480 tool-to-front cover bolts. Don-t tighten the bolts yet.
    NOTE
    Align the tapered legs of the tool with the machined alignment surfaces on the front cover.



    Click image to see an enlarged view

    Fig. Seal alignment tool installation-4.8L, 5.3L, 6.0L

  10.  
  11. Install tool J41476 . Install the crankshaft balancer bolt. Tighten the crankshaft balancer bolt by hand until snug. Do not overtighten. Tighten the J41480 bolts and front cover bolts to 25 Nm (18 ft. lbs.).
  12.  
  13. Remove the tools.
  14.  
  15. Place a straight edge across the engine block and front cover oil pan sealing surfaces. Avoid contact with the portion of the gasket that protrudes into the oil pan surface. Insert a feeler gauge between the front cover and the straight edge tool. The cover must be flush with the oil pan surface or no more than 0.5 mm (0.02 in) below flush. If the front cover-to-engine block oil pan surface alignment is not within specifications, repeat the cover alignment procedure. If the correct front cover-to-engine block alignment cannot be obtained, replace the front cover.
  16.  
  17. Install the crankshaft balancer bolt. Tighten the crankshaft balancer bolt by hand until snug. Do not overtighten the bolt.
  18.  
  19. Snug the oil pan-to-cover bolts in order to position the cover at the pan rail.
  20.  
  21. Tighten the oil pan-to-front cover bolts to 25 Nm (18 ft. lbs.).
  22.  
  23. Tighten the front cover bolts to 25 Nm (18 ft. lbs.).
  24.  
  25. Install the water pump.
  26.  

6.5L Engine
  1. Drain the cooling system.
  2.  
  3. Remove or disconnect the following:

    Negative battery cables
     
    Water pump and pulleys
     

  4.  
  5. Rotate the crankshaft to align the marks on the torsional damper with the 0 mark on the timing tab.
  6.  
  7. Scribe a mark aligning the injection pump flange and the front cover, if not already marked.
    NOTE
    The outer ring (weight) of the torsional damper is bonded to the hub with rubber. The damper must be removed with a puller that acts on the inner hub only. Pulling on the outer portion of the damper will break the rubber bond or destroy the tuning of the unit.

  8.  
  9. Remove or disconnect the following:

    Crankshaft pulley and torsional damper
     
    Front cover-to-oil pan bolts (4)
     
    2 fuel return line clips
     
    Injection pump gear
     
    Injection pump retaining nuts from the front cover
     
    Crankshaft sensor
     
    Baffle
     
    Cover bolts remaining and the front cover
     
    Injection pump gear
     

  10.  
  11. Align the camshaft timing gear marks

    Bolt and washer attaching the camshaft gear
     
    Camshaft sprocket with the timing chain
     
    Crankshaft sprocket.
     

  12.  

To install:

  1. Install or connect the following:

    Cam sprocket, timing chain and crankshaft sprocket as a unit, aligning the timing marks on the sprockets.
     

  2.  
  3. Rotate the crankshaft to align the injection pump and camshaft gears.

    Injection pump gear
     

  4.  
  5. If the front cover oil seal is to be replaced, it can now be pried out of the cover with a suitable prying tool. Press the new seal into the cover evenly.
  6.  
  7. Clean both sealing surfaces until all traces of old sealer are gone. Apply a 3 / 32 in. (2mm) bead of GM sealant 1052357 or equivalent to the sealing surface. Apply a 3 / 16 in. (5mm) bead of RTV type sealer to the bottom portion of the front cover which attaches to the oil pan.
    NOTE
    Verify that there is a minimum clearance of 0.040 in. (1.0mm) between the injection pump gear and baffle or noise may be result.



    Front cover
     
    Baffle
     
    Injection pump. Torque the nuts to 31 ft. lbs. (42 Nm), making sure the scribe marks on the pump and front cover are aligned.
     
    Injection pump driven gear. Torque the injection pump gear bolts to 17 ft. lbs. (23 Nm), making sure the marks on the cam gear and pump are aligned.
     



    Fuel line clips
     
    Front cover-to-oil bolts
     
    Torsional damper
     
    Crankshaft pulley. Torque the bolts to 80 inch lbs. (9 Nm).
     
    Oil pan bolts. Torque the bolts to 106 inch lbs. (12 Nm).
     
    Water pump
     
    Pulley assembly
     
    Negative battery cables
     

  8.  
  9. Refill the cooling system with the proper type and quantity of antifreeze.
  10.  
  11. Inspect the engine for leaks.

    Click image to see an enlarged view

    Fig. Timing chain and related components-6.5L diesel engines

  12.  

  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:

    Negative battery cables
     
    Water pump and pulleys
     

  6.  
  7. Rotate the crankshaft to align the marks on the torsional damper with the 0 mark on the timing tab.
  8.  
  9. Scribe a mark aligning the injection pump flange and the front cover, if not already marked.
    NOTE
    The outer ring (weight) of the torsional damper is bonded to the hub with rubber. The damper must be removed with a puller that acts on the inner hub only. Pulling on the outer portion of the damper will break the rubber bond or destroy the tuning of the unit.

  10.  
  11. Remove or disconnect the following:

    Crankshaft pulley and torsional damper
     
    Front cover-to-oil pan bolts (4)
     
    2 fuel return line clips
     
    Injection pump gear
     
    Injection pump retaining nuts from the front cover
     
    Crankshaft sensor
     
    Baffle
     
    Cover bolts remaining and the front cover
     
    Injection pump gear
     

  12.  
  13. Align the camshaft timing gear marks
  14.  
  15. Remove the bolt and washer attaching the camshaft gear.

    Camshaft sprocket with the timing chain. Remove the crankshaft sprocket.
     

  16.  

To install:

  1. Install or connect the following:

    Cam sprocket, timing chain and crankshaft sprocket as a unit, aligning the timing marks on the sprockets.
     

  2.  
  3. Rotate the crankshaft to align the injection pump and camshaft gears.

    Injection pump gear
     

  4.  
  5. If the front cover oil seal is to be replaced, it can now be pried out of the cover with a suitable prying tool. Press the new seal into the cover evenly.
  6.  
  7. Clean both sealing surfaces until all traces of old sealer are gone. Apply a 3 / 32 in. (2mm) bead of GM sealant 1052357 or equivalent to the sealing surface. Apply a 3 / 16 in. (5mm) bead of RTV type sealer to the bottom portion of the front cover which attaches to the oil pan. Install the front cover.
    NOTE
    Verify that there is a minimum clearance of 0.040 in. (1.0mm) between the injection pump gear and baffle or noise may be result.



    Baffle
     
    Injection pump. Torque the nuts to 31 ft. lbs. (42 Nm), making sure the scribe marks on the pump and front cover are aligned.
     
    Injection pump driven gear. Torque the injection pump gear bolts to 17 ft. lbs. (23 Nm), making sure the marks on the cam gear and pump are aligned.
     



    Fuel line clips
     
    Front cover-to-oil bolts
     
    Torsional damper
     
    Crankshaft pulley. Torque the bolts to 80 inch lbs. (9 Nm).
     
    Oil pan bolts. Torque the bolts to 106 inch lbs. (12 Nm).
     
    Water pump
     
    Pulley assembly
     
    Negative battery cables
     

  8.  
  9. Refill the cooling system with the proper type and quantity of antifreeze.
  10.  
  11. Inspect the engine for leaks.

    Click image to see an enlarged view

    Fig. Timing chain and related components-6.5L diesel engines

  12.  

  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:

    Negative battery cables
     
    Water pump and pulleys
     

  6.  
  7. Rotate the crankshaft to align the marks on the torsional damper with the 0 mark on the timing tab.
  8.  
  9. Scribe a mark aligning the injection pump flange and the front cover, if not already marked.
    NOTE
    The outer ring (weight) of the torsional damper is bonded to the hub with rubber. The damper must be removed with a puller that acts on the inner hub only. Pulling on the outer portion of the damper will break the rubber bond or destroy the tuning of the unit.

  10.  
  11. Remove or disconnect the following:

    Crankshaft pulley and torsional damper
     
    Front cover-to-oil pan bolts (4)
     
    2 fuel return line clips
     
    Injection pump gear
     
    Injection pump retaining nuts from the front cover
     
    Crankshaft sensor
     
    Baffle
     
    Cover bolts remaining and the front cover
     
    Injection pump gear
     

  12.  
  13. Align the camshaft timing gear marks
  14.  
  15. Remove the bolt and washer attaching the camshaft gear.

    Camshaft sprocket with the timing chain. Remove the crankshaft sprocket.
     

  16.  

To install:

  1. Install or connect the following:

    Cam sprocket, timing chain and crankshaft sprocket as a unit, aligning the timing marks on the sprockets.
     

  2.  
  3. Rotate the crankshaft to align the injection pump and camshaft gears.

    Injection pump gear
     

  4.  
  5. If the front cover oil seal is to be replaced, it can now be pried out of the cover with a suitable prying tool. Press the new seal into the cover evenly.
  6.  
  7. Clean both sealing surfaces until all traces of old sealer are gone. Apply a 3 / 32 in. (2mm) bead of GM sealant 1052357 or equivalent to the sealing surface. Apply a 3 / 16 in. (5mm) bead of RTV type sealer to the bottom portion of the front cover which attaches to the oil pan. Install the front cover.
    NOTE
    Verify that there is a minimum clearance of 0.040 in. (1.0mm) between the injection pump gear and baffle or noise may be result.



    Baffle
     
    Injection pump. Torque the nuts to 31 ft. lbs. (42 Nm), making sure the scribe marks on the pump and front cover are aligned.
     
    Injection pump driven gear. Torque the injection pump gear bolts to 17 ft. lbs. (23 Nm), making sure the marks on the cam gear and pump are aligned.
     



    Fuel line clips
     
    Front cover-to-oil bolts
     
    Torsional damper
     
    Crankshaft pulley. Torque the bolts to 80 inch lbs. (9 Nm).
     
    Oil pan bolts. Torque the bolts to 106 inch lbs. (12 Nm).
     
    Water pump
     
    Pulley assembly
     
    Negative battery cables
     

  8.  
  9. Refill the cooling system with the proper type and quantity of antifreeze.
  10.  
  11. Inspect the engine for leaks.

    Click image to see an enlarged view

    Fig. Timing chain and related components-6.5L diesel engines

  12.  

 
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