Bonneville, LeSabre, Park Avenue 2000-2005

Cylinder Head

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Removal & Installation



3.8L Engine
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Relieve the fuel system pressure.
  6.  
  7. Drain the cooling system.
  8.  
  9. Remove or disconnect the following:

    Intake manifold
     
    Exhaust manifold
     
    Valve covers
     
    Ignition wires and ignition coil/module assembly
     
    Alternator front mounting bracket and alternator
     
    Air conditioning bracket-to-cylinder head bolt
     
    Power steering pump
     
    Accessory drive belt tensioner
     
    Supercharger belt tensioner, if equipped
     
    Fuel pipe heat shield
     
    Rocker arm assemblies, note their original position
     
    Pushrods and guide plate
     
    Cylinder head bolts
     
    Cylinder head
     

  10.  

To install:

  1. Place the new cylinder head gasket on the engine block dowels with the note THIS SIDE UP facing the cylinder head and the arrow facing the front of the engine. Position the cylinder head on the engine block.
    NOTE
    The head gasket is identified by either a L or a R stamped on it next to the arrow.


    NOTE
    This engine uses special torque-to-yield head bolts. The procedure must be followed carefully and new bolts must be used whenever the head is removed. Total bolt torque should not exceed 60 ft. lbs. (81 Nm).



    Click image to see an enlarged view

    Fig. Cylinder head bolt torque sequence-3.8L engine

  2.  
  3. Install new cylinder head bolts and torque them in sequence as follows:
    1. Step 1: 37 ft. lbs. (50 Nm).
    2.  
    3. Step 2: Plus 120 degrees.
    4.  

  4.  
  5. Install or connect the following:
    NOTE
    Apply a thread lock compound to the rocker arm pedestal bolts before assembly.



    Pushrods and guide plate
     
    Rocker arm assemblies into their original location
     



    Valve covers
     
    Fuel pipe heat shield
     
    Accessory drive belt tensioner
     
    Supercharger belt tensioner (VIN 1 engine)
     
    Power steering pump
     
    Air conditioning compressor bracket bolt. Torque it to 52 ft. lbs. (70 Nm).
     
    Alternator front mounting bracket, and alternator
     
    Ignition coil/module assembly and spark plug wires
     
    Exhaust manifold. Torque the bolts to 22 ft. lbs. (30 Nm).
     
    Intake manifold
     
    Negative battery cable
     

  6.  
  7. Refill and bleed the cooling system.
  8.  
  9. Start the engine and check for leaks and proper operation.
  10.  

4.6L Engine
Left Side
  1. Remove the following subassemblies:

    The left exhaust manifold.
     
    The generator.
     
    The water crossover.
     
    The intake manifold.
     
    The camshaft cover.
     
    The engine front cover.
     
    The left secondary camshaft drive chain.
     

  2.  
  3. Remove the power steering return hose retaining bolt from the cylinder head.
  4.  
  5. Remove the 3 M6 external drive bolts from the front portion of the cylinder head.
    NOTE
    DO NOT reuse the M11 cylinder head bolts.

  6.  
  7. Remove and discard the ten M11 internal drive cylinder head bolts.
  8.  
  9. Remove the left cylinder head. Make sure that no dowel guide pins are stuck in the cylinder head.
    NOTE
    You must clean the thread sealant material from the cylinder head bolt holes in the cylinder block. Failure to do so could cause false torque readings during reassembly. After removing the cylinder head, remove any remaining bolt thread sealant material from the threaded cylinder block holes.


    NOTE
    DO NOT reuse the cylinder head gasket.

  10.  
  11. Remove the left cylinder head gasket.
  12.  
  13. Remove all remaining gasket material from the cylinder head and cylinder block using tool J 28410.
  14.  
  15. Place the cylinder head on a flat, clean surface with the combustion chambers face-up in order to prevent damage to the deck face.
  16.  
  17. Clean and inspect the cylinder head.
  18.  

To install:

Click image to see an enlarged view

Fig. Left cylinder head bolt torque sequence-4.6L engine

  1. Make sure all the cylinder head locating pins are securely mounted in the cylinder block deck face.
    NOTE
    Failure to remove all the old thread sealant material from the cylinder block could cause false torque readings.

  2.  
  3. Make sure any old thread sealant material is removed from the cylinder head bolt holes in the cylinder block.
  4.  
  5. Install a new left cylinder head gasket using the deck face locating pins for retention.
  6.  
  7. Align the cylinder head with the deck face locating pins.
  8.  
  9. Place the cylinder head in position on the deck face.
    NOTE
    DO NOT reuse the old M11 cylinder head bolts.

  10.  
  11. Install new M11 cylinder head bolts in the cylinder head.
  12.  
  13. Install the M6 cylinder head bolts at the front of the cylinder head.
  14.  
  15. Tighten the left cylinder head bolts in the sequence shown.
    1. First Pass: Tighten the left cylinder head M11 cylinder head bolts to 30 ft. lbs. (40 Nm) in the sequence shown.
    2.  
    3. Second Pass: Tighten the left cylinder head M11 cylinder head bolts an additional 70 degrees in the sequence shown.
    4.  
    5. Third Pass: Repeat the sequence turning each bolt another 60 degrees.
    6.  
    7. Final Pass: Repeat the sequence again turning each bolt a final 45 degrees (total 175 degrees).
    8.  

  16.  
  17. Tighten the M6 bolts at the front of the cylinder head to 106 inch lbs. (12 Nm).
  18.  
  19. Install the power steering return hose retaining bolt to the cylinder head. Tighten the power steering return hose retaining bolt to 37 ft. lbs. (50 Nm).
  20.  
  21. Install the following subassemblies:

    The left secondary camshaft drive chain.
     
    The engine front cover.
     
    The camshaft cover.
     
    The intake manifold.
     
    The water crossover.
     
    The generator.
     
    The left exhaust manifold.
     

  22.  

Right Side
  1. Remove the following subassemblies:

    The right exhaust manifold.
     
    The water crossover.
     
    The intake manifold.
     
    The camshaft cover.
     
    The engine front cover.
     
    The right secondary camshaft drive chain.
     

  2.  
  3. Disconnect the electrical connector from the ECT sensor.
  4.  
  5. Remove the nut securing the coil cassette ground wire to the cylinder head.
  6.  
  7. Remove the bolt securing the exhaust crossover pipe to the cylinder head.
  8.  
  9. Raise and support the vehicle.
  10.  
  11. Remove the bolt securing the front transaxle brace to the cylinder head.
  12.  
  13. Loosen the bolts attaching the transaxle brace to the transaxle.
  14.  
  15. Remove the bolt securing the rear transaxle brace to the transaxle.
  16.  
  17. Lower the vehicle.
  18.  
  19. Remove the nuts securing the rear transaxle brace to the cylinder head.
  20.  
  21. Remove the rear transaxle brace.
  22.  
  23. Remove the 3 M6 external drive bolts from the front portion of the cylinder head.
    NOTE
    DO NOT reuse the M11 cylinder head bolts.

  24.  
  25. Remove and discard the ten M11 internal drive cylinder head bolts.
  26.  
  27. Remove the right cylinder head. Make sure that no dowel guide pins are stuck in the cylinder head.
    NOTE
    You must clean the thread sealant material from the cylinder head bolt holes in the cylinder block. Failure to do so could cause false torque readings during reassembly.

  28.  
  29. After removing the cylinder head, remove any remaining bolt thread sealant material from the threaded cylinder block holes.
    NOTE
    DO NOT reuse the cylinder head gasket.

  30.  
  31. Remove the right cylinder head gasket.
  32.  
  33. Remove all remaining gasket material from the cylinder head and cylinder block.
  34.  
  35. Place the cylinder head on a flat, clean surface with the combustion chambers face-up in order to prevent damage to the deck face.
  36.  
  37. Clean and inspect the cylinder head.
  38.  

To install:

Click image to see an enlarged view

Fig. Right cylinder head torque sequence-4.6L engine

  1. Make sure all the cylinder head locating pins are securely mounted in the cylinder block deck face.
    NOTE
    Failure to remove all the old thread sealant material from the cylinder block could cause false torque readings.

  2.  
  3. Make sure any old thread sealant material is removed from the cylinder head bolt holes in the cylinder block.
  4.  
  5. Install a new right cylinder head gasket using the deck face locating pins for retention.
  6.  
  7. Align the cylinder head with the deck face locating pins.
  8.  
  9. Place the cylinder head in position on the deck face.
    NOTE
    DO NOT reuse the old M11 cylinder head bolts.

  10.  
  11. Install new M11 cylinder head bolts in the cylinder head.
  12.  
  13. Install the M6 cylinder head bolts at the front of the cylinder head.
  14.  
  15. Tighten the right cylinder head bolts in the sequence shown.
    1. First Pass: Tighten the right cylinder head M11 cylinder head bolts to 30 ft. lbs. (40 Nm) in the sequence shown.
    2.  
    3. Second Pass: Tighten the right cylinder head M11 cylinder head bolts an additional 70 degrees in the sequence shown.
    4.  
    5. Third Pass: Repeat the sequence turning each bolt another 60 degrees.
    6.  
    7. Final Pass: Repeat the sequence again turning each bolt a final 45 degrees (total 175 degrees).
    8.  

  16.  
  17. Tighten the M6 bolts at the front of the cylinder head to 106 inch lbs. (12 Nm).
  18.  
  19. Position the rear transaxle brace over the studs located at the rear of the right cylinder head.
  20.  
  21. Loosely install the nuts securing the rear transaxle brace to the cylinder head.
  22.  
  23. Raise and support the vehicle.
  24.  
  25. Install the bolt securing the rear transaxle brace to the transaxle. Tighten the rear transaxle brace bolt to 37 ft. lbs. (50 Nm).
  26.  
  27. Install the bolt securing the front transaxle brace to the cylinder head. Tighten the front transaxle brace bolts to 37 ft. lbs. (50 Nm).
  28.  
  29. Lower the vehicle.
  30.  
  31. Tighten the rear transaxle brace to the cylinder head nuts to 37 ft. lbs. (50 Nm).
  32.  
  33. Connect the electrical connector to the ECT sensor.
  34.  
  35. Install the bolt securing the exhaust crossover pipe to the cylinder head. Tighten the exhaust crossover pipe to cylinder head bolt to 18 ft. lbs. (25 Nm).
  36.  
  37. Install the nut securing the coil cassette ground wire to the cylinder head. Tighten the coil cassette ground wire nut to 13 ft. lbs. (17 Nm).
  38.  
  39. Install the following subassemblies:

    The right secondary camshaft drive chain.
     
    The engine front cover.
     
    The camshaft cover.
     
    The intake manifold.
     
    The water crossover.
     
    The right exhaust manifold.
     

  40.  

 
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