Envoy, Rainer, Trailblazer 2006-2007

Camshaft, Bearings & Lifters

Print

Bearing Replacement



5.3L & 6.0L Engines


Click image to see an enlarged view

Fig. Removal of camshaft bearings-5.3L and 6.0L engines


NOTE
A loose camshaft bearing may be caused by an enlarged, out of round, or damaged engine block bearing bore.

  1. Prior to bearing removal, inspect the camshaft bearings for loose fit in the engine block bearing bores.
  2.  
  3. Repair or replace the components, as required.
  4.  
  5. Select the expanding driver and washer from special tool J-33049.
  6.  
  7. Assemble the tool.
  8.  
  9. Insert the tool through the front of the engine block and into the bearing.
  10.  
  11. Tighten the expander assembly nut until snug.
  12.  
  13. Push the guide cone into the front camshaft bearing location in order to align the tool.

    Click image to see an enlarged view

    Fig. Drive the bearing from the block bore-5.3L and 6.0L engines

  14.  
  15. Drive the bearing from the block bore.
    NOTE
    In order to remove the front camshaft bearing, operate the tool from the rear of the block, using the guide cone in the rear camshaft bearing bore location.

  16.  
  17. Repeat the above procedures in order to remove the remaining bearings.
  18.  

To install:

Click image to see an enlarged view

Fig. Camshaft bearing positions in the engine block-5.3L and 6.0L engines


NOTE
The engine block camshaft bearing bores are machined for 3 different outside diameter (OD) size bearings. Position 1 and 5 are the largest diameter bores. Position 3 is the smallest diameter bore. Position 2 and 4 are the intermediate size bores. The inside diameter (ID) for all camshaft bearings is the same size.

  1. Measure the engine block camshaft bearing bores (1-5) in order to identify the correct OD size bearing for each position.
  2.  
  3. Select the expanding driver and washer from special tool J-33049.
  4.  
  5. Assemble the tool.
  6.  
  7. Insert the tool through the front of the engine block and into the bearing.
  8.  
  9. Tighten the expander assembly nut until snug.

    Click image to see an enlarged view

    Fig. Align the tool by pushing the cone (2) into the front camshaft bearing location-5.3L and 6.0L engines

  10.  
  11. Push the cone (2) into the front camshaft bearing location in order to align the tool.
  12.  
  13. Drive the bearing into the block bore.
  14.  
  15. Install the front and rear bearings to the block.
  16.  

Inspection



Using solvent, degrease the camshaft and clean out all of the oil holes. Visually inspect the cam lobes and bearing journals for excessive wear. If a lobe is questionable, check all of the lobes as indicated. If a journal or lobe is worn, the camshaft MUST BE reground or replaced.

Click image to see an enlarged view

Fig. Checking the camshaft for straightness



Click image to see an enlarged view

Fig. Measuring camshaft lobe lift


NOTE
If a journal is worn, there is a good chance that the bearings are worn and need replacement.

If the lobes and journals appear intact, place the front and rear journals in V-blocks and rest a dial indicator on the center journal. Rotate the camshaft to check the straightness. If deviation exceeds 0.001 in. (0.0254mm), the camshaft should likely be replaced.


NOTE
On most engines lobe lift can be measured with the camshaft still installed. Simply remove the rocker cover and rocker arm, then use a dial gauge on the end of the pushrod. When the pushrod is at the bottom of its travel, set the dial gauge to -0'' then turn the engine and note the gauge's highest reading.

Check the camshaft lobes with a micrometer, by measuring the across the lobe centerline from the nose to the base and again at the centerline across the diameter at 90° from the first measurement (see illustration). The lobe lift is determined by subtracting the second measurement (diameter) from the first (diameter plug lobe lift). If the lobes vary from specification, the camshaft must be reground or replace.

Removal & Installation



4.2L Engine
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Discharge and recover the refrigerant from the air conditioning system, using the proper equipment.
  6.  
  7. Remove or disconnect the following:
    WARNING
    Be careful not to damage the clips that hold the harness housing in place.



    Intake manifold
     
    A/C line from the oil level indicator tube
     
    A/C line from the accumulator
     
    A/C bracket bolt from the engine lift hook
     
    Engine lift bracket
     
    Ignition control module electrical connectors
     
    Ignition control module bolts and module
     



    Engine electrical harness housing from the camshaft cover
     
    Fuel injection harness electrical connector
     
    Camshaft cover bolts and cover
     
    Exhaust and intake sprocket bolts
     

  8.  
  9. Install a suitable sprocket holding tool onto the cylinder head and adjust the horizontal bolts into the camshaft sprockets to maintain timing chain tension and avoid disturbing the timing chain components.
  10.  
  11. Carefully move the sprockets with the timing chain off of the camshafts.
    NOTE
    Make sure to place the camshaft caps in a rack to keep them in order, so they may be installed in their original locations.

  12.  
  13. Remove or disconnect the following:

    Camshaft cap bolts and caps
     
    Camshafts
     

  14.  

To install:

  1. Coat the camshaft journals with engine oil.

    Camshafts, in their original position
     
    Camshaft caps, in their original locations. Tighten the bolts to 106 inch lbs. (12 Nm).
     

  2.  
  3. Carefully place the camshaft sprockets back onto the camshafts and remove the holding tool.
  4.  
  5. Install or connect the following:

    Intake camshaft sprocket washer and bolt and the exhaust camshaft actuator bolt. Tighten the intake camshaft sprocket bolt to 22 ft. lbs. (30 Nm), plus an additional 135 degrees and the exhaust camshaft actuator bolt to 18 ft. lbs. (25 Nm), plus an additional 135 degrees.
     
    New camshaft cover seal
     
    New rubber ignition control module seals
     
    Camshaft cover and bolts. Tighten the bolts to 89 inch lbs. (10 Nm).
     
    Ignition control module. Tighten the bolts to 89 inch lbs. (10 Nm).
     
    Ignition control module electrical connectors
     
    Fuel injector electrical connectors
     
    Engine electrical harness housing
     
    A/C line bracket to the oil level indicator tube stud and secure with the nut. Tighten the nut to 62 inch lbs. (7 Nm).
     
    Engine lift bracket and secure the lift hook with the bolts. Tighten the bolts to 37 ft. lbs. (50 Nm).
     
    A/C line bracket to the engine lift bracket. Tighten the bolt to 89 inch lbs. (10 Nm).
     
    Intake manifold
     

  6.  
  7. Using the proper equipment, recharge the A/C system.
  8.  

5.3L & 6.0L Engines
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Discharge and recover the refrigerant from the air conditioning system, using the proper equipment.
  6.  
  7. Remove or disconnect the following:
    NOTE
    If the lifters are stuck in the bores due to built up deposits, use Valve Lifter Remover tool No. J 3049-A or equivalent to remove the lifters


    NOTE
    Make sure to keep the lifters in order as you are removing them. They must be installed in their original locations.



    Condenser
     
    Cylinder head and gasket
     
    Valve lifter guide bolts
     
    Valve lifters and guide
     



    Valve lifters from the guide
     



    Click image to see an enlarged view

    Fig. Valve lifters and guides-5.3L and 6.0L engines



    Click image to see an enlarged view

    Fig. Remove the lifters from the guides, making sure to keep them in order-5.3L and 6.0L engines

  8.  
  9. Clean and inspect the lifters for damage.

    Camshaft sensor bolt and sensor
     

  10.  
  11. Rotate the crankshaft until the timing marks on the crankshaft and camshaft sprockets are aligned.
    WARNING
    Do NOT turn the crankshaft after the timing chain has been removed to avoid damaging the pistons or valves!


    NOTE
    Take care not to damage the camshaft bearings when removing the camshaft.



    Camshaft sprocket bolts

    Click image to see an enlarged view

    Fig. Make sure the crankshaft and camshaft timing marks are aligned

     



    Camshaft sprocket and reposition the timing chain
     
    Camshaft retaining bolts and retainer
     
    Camshaft by installing three M8-1.25 x 4.0 in. (M8-1.25 x 1.00mm) bolts in the front of the camshaft to act as a handle; then, remove the camshaft while turning slightly from side to side, as necessary. Remove the bolts from the camshaft.
     

  12.  
  13. Clean and inspect the camshaft and bearings.
  14.  

To install:


NOTE
If the camshaft must be replaced, you must also replace the lifters.

  1. Lubricate the camshaft journals with clean engine oil.
  2.  
  3. Install or connect the following:

    Three bolts used during removal into the bolt hold in the front of the camshaft
     
    Camshaft carefully into the engine block, using the bolts as a handle. Remove the bolts.
     
    Camshaft retainer and bolts. Make sure the retaining plate is installed with the sealing gasket facing the engine block. Tighten the bolts to 18 ft. lbs. (25 Nm).
     

  4.  
  5. Properly locate the camshaft sprocket locating pin with the cam sprocket alignment hole. The sprocket teeth and timing chain must mesh. The camshaft and crankshaft sprocket alignment marks MUST be aligned properly. Locate the camshaft sprocket alignment mark in the 6 o-clock position. It may be necessary to rotate the camshaft or crankshaft to align the marks.

    Camshaft sprocket and timing chain
     
    Camshaft sprocket bolts and tighten to 26 ft. lbs. (35 Nm)
     
    Camshaft sensor O-ring, after making sure it is not damaged and lubricating it with clean engine oil
     
    Camshaft sensor and bolt. Torque the bolt to 18 ft. lbs. (25 Nm).
     

  6.  
  7. Lubricate the valve lifters and engine block lifter bores with clean engine oil.
  8.  
  9. Install or connect the following:

    Lifters into the lifter guides. Align the area on top of the lifter with the flat area in the lifter guide bore. Push the lifter completely into the guide bore.
     
    Valve lifters and guide to the engine block
     
    Valve lifter guide bolt and tighten to 106 inch lbs. (12 Nm)
     
    Cylinder head and gasket
     
    Condenser
     

  10.  
  11. Using the proper equipment, recharge the A/C system.
  12.  

 
label.common.footer.alt.autozoneLogo