Pacifica 2006-2008

Camshaft, Bearings & Lifters

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Inspection



3.5L & 4.0L Engines
  1. Inspect camshaft bearing journals for damage and binding. If journals are binding, check the cylinder head for damage. Also check cylinder head oil holes for clogging.
  2.  
  3. Check the cam lobe and bearing surfaces for abnormal wear and damage. Replace camshaft if defective.
    NOTE
    If the camshaft is replaced due to lobe wear or damage, always replace the rocker arms.

  4.  
  5. Measure the lobe actual wear and replace camshaft if out of limit. Standard value is 0.001 in. (0.0254mm), wear limit is 0.010 in. (0.254mm).

    Click image to see an enlarged view

    Fig. Measure the lobe actual wear (1), left camshaft (2), right camshaft (3), bearing journal (4) and camshaft lobe (5)-3.5L engine

  6.  

3.8L Engine
  1. Check the cam lobes and bearing surfaces for abnormal wear and damage. Replace camshaft as required.
    NOTE
    If camshaft is replaced due to lobe wear or damage, always replace the lifters.

  2.  
  3. Measure the lobe actual wear (unworn area - wear zone = actual wear) and replace camshaft if out of limit. Standard value is 0.001 in. (0.0254mm), wear limit is 0.010 in. (0.254mm).

    Click image to see an enlarged view

    Fig. Camshaft unworn area (1), actual wear (2), bearing journal (3), lobe (4) and wear zone (5)-3.8L engine

  4.  

Removal & Installation



3.5L & 4.0L Engines
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  

Camshafts are serviced from the rear of the cylinder head. Although the engine does not need to be removed for camshaft service, the cylinder head must be removed from the vehicle. Note too, that the camshaft sprockets have a D-shaped hole that allows it to rotate several degrees in each direction on its shaft.

  1. Properly relieve the fuel system pressure.
  2.  
  3. Drain the cooling system.
  4.  
  5. Remove or disconnect the following:
    NOTE
    Mark the rocker arm assembly to note component locations before disassembly.



    Cylinder head bolts and cylinder head
     

  6.  
  7. Remove the rocker arm and shaft assemblies.
  8.  
  9. Remove the rear camshaft cover and O-ring.
    WARNING
    Carefully, remove the camshaft from the rear of the head taking care not to nick or scratch the journals.

  10.  
  11. Inspect camshaft journals for wear or damage. If wear is present, inspect the cylinder head for damage. Inspect the head oil holes for clogging. Replace the camshaft as required.
  12.  
  13. Measure the height of the cam using a micrometer. Measure in 2 places: the unworn area and in the wear zone. Subtract the figures to get cam wear. The standard specification is 0.001 in. (0.0254mm) with the wear limit being 0.010 in. (0.254mm). Replace the camshaft if it is worn beyond this specification.

    Click image to see an enlarged view

    Fig. Exploded view of the camshaft assembly-3.5L and 4.0L engines



    Click image to see an enlarged view

    Fig. Measure the camshaft to ensure it meets specifications, if the camshaft is worn beyond the specifications it must be replaced-3.5L and 4.0L engines

  14.  

To install:

Click image to see an enlarged view

Fig. Rocker arm/shaft tightening sequence-3.5L and 4.0L engines

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

    Camshaft
     
    Camshaft cover and O-ring and torque the bolts to 21 ft. lbs. (28 Nm)
     
    Rocker arm assemblies
     
    Cylinder head assembly
     
    Negative battery cable
     

  4.  
  5. Fill and bleed the cooling system. An oil and filter change is recommended.
  6.  
  7. Start the vehicle, check for leaks and repair if necessary.
  8.  

3.8L Engine

NOTE
Keep all valvetrain components in order for assembly.

  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Remove the engine from the vehicle and mount it on a stand.
  4.  
  5. Remove or disconnect the following:

    Valve covers
     
    Rocker arm and shaft assemblies
     
    Pushrods
     
    Intake manifold
     
    Cylinder heads
     
    Yoke retainer
     
    Aligning yokes
     
    Hydraulic lifters
     
    Oil pan
     
    Oil pump pickup tube
     
    Crankshaft pulley
     
    Front cover
     
    Timing chain and sprockets
     
    Camshaft thrust plate
     
    Camshaft
     

  6.  

To install:

  1. Install or connect the following:

    Camshaft
     
    Camshaft thrust plate. Torque the bolts to 105 inch lbs. (12 Nm).
     
    Timing chain and sprockets. Torque the camshaft sprocket bolt to 40 ft. lbs. (54 Nm).
     
    Front cover. Torque the bolts to 20 ft. lbs. (27 Nm).
     
    Crankshaft pulley. Torque the bolt to 40 ft. lbs. (54 Nm).
     
    Oil pump pickup tube
     
    Oil pan
     
    Hydraulic lifters
     
    Aligning yokes
     
    Yoke retainer. Torque the bolts to 105 inch lbs. (12 Nm).
     
    Cylinder heads
     
    Intake manifold
     
    Pushrods
     
    Rocker arm and shaft assemblies
     
    Valve covers
     

  2.  
  3. Install the engine to the vehicle.

    Click image to see an enlarged view

    Fig. Remove the thrust plate and withdraw the camshaft from the engine-3.8L engine

  4.  

 
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