Pacifica, 2003-2005

Cylinder Head

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Removal & Installation



3.5L Engine
Left Side
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Properly relieve the fuel system pressure.
  4.  
  5. Drain the cooling system.
  6.  
  7. Remove or disconnect the following:

    Negative battery cable
     
    Engine cover
     
    Air cleaner assembly
     
    Radiator close out panel
     
    Radiator core support and fan assembly
     
    Fuel line from the rail
     
    Upper intake manifold
     
    Lower intake manifold
     
    Crankshaft damper
     
    Upper engine mount
     
    Upper drive belt idler pulley
     
    Belt tensioner
     
    Left exhaust manifold
     
    Exhaust cross over pipe
     
    Outer timing belt cover
     

  8.  
  9. Rotate the engine until it is at Top Dead center (TDC).
    NOTE
    Mark the timing belt running direction for installation. Align the camshaft sprockets with the marks on the rear covers.



    Timing belt tensioner and reset the tensioner. Refer to the timing belt removal and installation procedure in this section.
     

  10.  
  11. Pre-load the timing belt tensioner as follows:
    1. Place tensioner in a vise the same way it is mounted on the engine.
    2.  
    3. Slowly compress the plunger into the tensioner body.
    4.  
    5. Once the plunger is compressed, install a pin through the body and plunger to retain it in place until the tensioner is installed.

      Timing belt. Refer to the timing belt removal and installation procedure in this section.
       
      Left cylinder head cover
       
      Left rocker arm assembly
       
      Left rear camshaft thrust plate
       
      Holding the camshaft gear, unfasten the right cam gear retaining bolt
       

    6.  

  12.  
  13. Push the camshaft about 3.5 inches out of the back of the cylinder head and remove the cam gear.

    Front timing belt housing-to-cylinder head bolts
     
    Cylinder head bolts in the reverse of tightening sequence. Refer to the cylinder head bolt tightening sequence illustration.
     
    Cylinder head and gasket.
     

  14.  

To install:

  1. Thoroughly clean and dry the mating surfaces of the head and block.
    WARNING
    When cleaning the cylinder head and block mating surfaces, do not use a metal scraper because the soft aluminum surfaces could be cut or damaged. Instead, use a scraper made of wood or plastic.

  2.  
  3. Check the cylinder head for cracks, damage or engine coolant leakage. Check the head for flatness. End-to-end, the head should be within 0.002 in. (0.051mm) normally with 0.008 in. (0.203mm) the maximum allowed out of true. The resurface limit is 0.008 in. (0.203mm) maximum, the combined total dimension of stock removal from the cylinder head, if any, and block top surface.
  4.  
  5. Place a new head gasket on the cylinder block locating dowels, being sure the gasket is on the correct side.
  6.  
  7. Inspect the cylinder head bolts for necking (stretching) by holding a straightedge against the threads of each bolt. If all of the threads are not contacting the scale, the bolt should be replaced.
    WARNING
    Due to the cylinder head bolt torque method used, it is imperative that the threads of the bolts be inspected for necking prior to installation. If the threads are necked down, the bolt should be replaced. Failure to do so may result in parts failure or damage. New bolts are always recommended.

  8.  
  9. Install the cylinder head into position on the engine block and over the dowels. Install the cylinder head bolts, lubricating the threads with clean engine oil prior to installation.
  10.  
  11. Torque the cylinder head bolts using the proper sequence as follows:
    1. Step 1: torque in sequence to 45 ft. lbs. (61 Nm).
    2.  
    3. Step 2: torque in sequence to 65 ft. lbs. (88 Nm).
    4.  
    5. Step 3: torque in sequence to 65 ft. lbs. (88 Nm).
    6.  
    7. Step 4: torque in sequence an additional 1 / 4 turn by using a torque angle meter.
      NOTE
      Inspect the bolt torque after tightening. The torque should be over 90 ft. lbs. (122 Nm). If not, replace the cylinder head bolt.



      Click image to see an enlarged view

      Fig. Cylinder head bolt tightening sequence-3.5L engine

      Cylinder head bolt tightening sequence-3.5L engine
    8.  

  12.  
  13. Install or connect the following:

    Inner timing cover-to-cylinder head bolts and tighten to 40 ft. lbs. (54 Nm)
     
    Cam gear, holding the camshaft gear, fasten the right cam gear retaining bolt to 75 ft. lbs. (102 Nm) plus an additional 1 / 4 turn
     
    Rear camshaft thrust plate
     

  14.  
  15. Rotate the camshaft gear until it is properly aligned and check the left camshaft gear and crankshaft timing alignment marks.

    Timing belt. Refer to the timing belt removal and installation procedure in this section.
     
    Timing belt front cover
     
    Crankshaft damper
     
    Upper engine mount
     
    Belt tensioner
     
    Upper drive belt idler pulley
     
    Left exhaust manifold
     
    Exhaust cross over pipe
     
    Left rocker arm assembly
     
    Left cylinder head cover
     
    Lower drive belt idler pulley
     
    Lower intake manifold and fuel rail
     
    Upper intake manifold
     
    Fuel line to the rail
     
    Radiator core support and fan assembly
     
    Radiator close out panel
     
    Drive belt
     
    Air cleaner assembly
     
    Engine cover
     
    Negative battery cable
     

  16.  

Right Side
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Properly relieve the fuel system pressure.
  4.  
  5. Drain the cooling system.
  6.  
  7. Remove or disconnect the following:

    Negative battery cable
     
    Engine cover
     
    Air cleaner assembly
     
    Fuel line from the rail
     
    Upper intake manifold
     
    Lower intake manifold
     
    Right front wheel
     
    Right inner splash shield
     
    Drive belt
     
    Crankshaft damper using the proper puller
     
    Lower drive belt idler pulley
     
    Power steering bolts and set the pump aside
     
    Lower timing belt cover bolts
     
    Catalytic converter nuts
     
    Oxygen (O 2 S) sensor electrical wiring at the exhaust manifold and catalytic converter
     
    Muffler-to-tail pipe union
     
    Catalytic converter
     
    Exhaust cross over pipe lower bolts
     
    Right exhaust manifold
     
    Upper drive belt idler pulley
     
    Belt tensioner
     

  8.  
  9. Support the engine with jackstands and wood blocks.

    Upper engine mount
     
    Power steering reservoir bolts and set aside
     
    All remaining outer timing belt cover bolts
     

  10.  
  11. Rotate the engine until it is at Top Dead center (TDC).
    NOTE
    Mark the timing belt running direction for installation. Align the camshaft sprockets with the marks on the rear covers.



    Timing belt tensioner and reset the tensioner. Refer to the timing belt removal and installation procedure in this section.
     

  12.  
  13. Pre-load the timing belt tensioner as follows:
    1. Place tensioner in a vise the same way it is mounted on the engine.
    2.  
    3. Slowly compress the plunger into the tensioner body.
    4.  
    5. Once the plunger is compressed, install a pin through the body and plunger to retain it in place until the tensioner is installed.

      Timing belt. Refer to the timing belt removal and installation procedure in this section.
       
      Right vale cover
       
      Exhaust Gas Recirculation (EGR) and tube assembly
       
      Right cylinder head cover
       
      Right rocker arm assembly
       
      Right rear camshaft thrust plate
       
      Holding the camshaft gear, unfasten the right cam gear retaining bolt
       

    6.  

  14.  
  15. Push the camshaft about 3.5 inches out of the back of the cylinder head and remove the cam gear.

    Inner timing cover-to-cylinder head bolts
     
    Cylinder head bolts in the reverse of tightening sequence. Refer to the cylinder head bolt tightening sequence illustration.
     
    Cylinder head and gasket.
     

  16.  

To install:

  1. Thoroughly clean and dry the mating surfaces of the head and block.
    WARNING
    When cleaning the cylinder head and block mating surfaces, do not use a metal scraper because the soft aluminum surfaces could be cut or damaged. Instead, use a scraper made of wood or plastic.

  2.  
  3. Check the cylinder head for cracks, damage or engine coolant leakage. Check the head for flatness. End-to-end, the head should be within 0.002 in. (0.051mm) normally with 0.008 in. (0.203mm) the maximum allowed out of true. The resurface limit is 0.008 in. (0.203mm) maximum, the combined total dimension of stock removal from the cylinder head, if any, and block top surface.
  4.  
  5. Place a new head gasket on the cylinder block locating dowels, being sure the gasket is on the correct side.
  6.  
  7. Inspect the cylinder head bolts for necking (stretching) by holding a straightedge against the threads of each bolt. If all of the threads are not contacting the scale, the bolt should be replaced.
    WARNING
    Due to the cylinder head bolt torque method used, it is imperative that the threads of the bolts be inspected for necking prior to installation. If the threads are necked down, the bolt should be replaced. Failure to do so may result in parts failure or damage. New bolts are always recommended.

  8.  
  9. Install the cylinder head into position on the engine block and over the dowels. Install the cylinder head bolts, lubricating the threads with clean engine oil prior to installation.
  10.  
  11. Torque the cylinder head bolts using the proper sequence as follows:
    1. Step 1: torque in sequence to 45 ft. lbs. (61 Nm).
    2.  
    3. Step 2: torque in sequence to 65 ft. lbs. (88 Nm).
    4.  
    5. Step 3: torque in sequence to 65 ft. lbs. (88 Nm).
    6.  
    7. Step 4: torque in sequence an additional 1 / 4 turn by using a torque angle meter.
      NOTE
      Inspect the bolt torque after tightening. The torque should be over 90 ft. lbs. (122 Nm). If not, replace the cylinder head bolt.



      Click image to see an enlarged view

      Fig. Cylinder head bolt tightening sequence-3.5L engine

      Cylinder head bolt tightening sequence-3.5L engine
    8.  

  12.  
  13. Install or connect the following:

    Inner timing cover-to-cylinder head bolts and tighten to 40 ft. lbs. (54 Nm)
     
    Cam gear, holding the camshaft gear, fasten the right cam gear retaining bolt to 75 ft. lbs. (102 Nm) plus an additional 1 / 4 turn
     
    Rear camshaft thrust plate
     

  14.  
  15. Rotate the camshaft gear until it is properly aligned and check the left camshaft gear and crankshaft timing alignment marks.

    Timing belt. Refer to the timing belt removal and installation procedure in this section.
     
    Timing belt outer cover
     
    Power steering reservoir
     
    Crankshaft damper
     
    Upper engine mount
     
    Belt tensioner
     
    Upper drive belt idler pulley
     
    Right exhaust manifold
     
    Exhaust cross over pipe
     
    Catalytic converter
     
    Muffler-to-tail pipe union
     
    O 2 S sensor electrical wiring at the exhaust manifold and catalytic converter
     
    Right rocker arm assembly
     
    Right cylinder head cover
     
    EGR and tube assembly
     
    Lower drive belt idler pulley
     
    Right vale cover
     
    Lower intake manifold and fuel rail
     
    Upper intake manifold
     
    Fuel line to the rail
     
    Power steering pump
     
    Drive belt
     
    Air cleaner assembly
     
    Engine cover
     
    Right inner splash shield
     
    Right front wheel
     
    Negative battery cable
     

  16.  

3.8L Engine
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Drain the cooling system.
  4.  
  5. Relieve the fuel system pressure.
  6.  
  7. Remove or disconnect the following:
    CAUTION
    The intake manifold gaskets are made of a very thin metal and can cause injury if not properly handled.


    NOTE
    Keep all valvetrain components in order for assembly



    Negative battery cable
     
    Upper and lower intake manifolds
     



    Valve covers.
     
    Spark plugs
     
    Dipstick tube
     
    Exhaust manifolds
     



    Rocker arm and shaft assemblies
     
    Cylinder head bolts, heads and gaskets
     

  8.  
  9. Clean all gasket mating surfaces.
  10.  

To install:

  1. Examine the cylinder head bolts and replace any that have stretched.

    Click image to see an enlarged view

    Fig. Cylinder head torque sequence-3.8L engines

    Cylinder head torque sequence-3.8L engines
  2.  
  3. Install the cylinder head with a new gasket. The left bank gasket has an L on it and is located at the front of the engine. The right gasket has an R stamped on it and is located at the rear of the engine. Tighten the bolts in sequence, as follows:


    1. Step 1: Tighten bolts 1-8 to 45 ft. lbs. (61 Nm).
    2.  
    3. Step 2: Tighten bolts 1-8 to 65 ft. lbs. (88 Nm).
    4.  
    5. Step 3: Tighten bolts 1-8 to 65 ft. lbs. (88 Nm).
    6.  
    7. Step 4: Bolts 1-8 plus 90 degrees.
    8.  

  4.  
  5. Check that the torque on bolts 1-8 has exceeded 90 ft. lbs. (122 Nm). If not, replace the bolt.
  6.  
  7. Install or connect the following:

    Pushrods
     
    Rocker arm and shaft assemblies
     
    Valve covers
     
    Exhaust manifolds
     
    Dipstick tube with a new O-ring
     
    Spark plugs
     
    Intake manifolds
     
    Negative battery cable
     

  8.  
  9. Fill the cooling system.
  10.  
  11. Start the engine and check for leaks.
  12.  

 
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