Aurora 2001-2003

Timing Chain & Sprockets

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Removal & Installation



2.5L & 4.0L Engines
Left Side Secondary Chain

NOTE
The secondary timing chains can be removed without removing the engine from the vehicle.

  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Remove or disconnect the following:

    Negative battery cable
     
    Drive belt
     
    Tower-to-tower brace
     
    Exhaust Y-pipe at the converter
     
    Front wheels
     
    Wheel well splash shields
     
    Crankshaft balancer bolt
     

  4.  
  5. Support the engine cradle.

    3 right-side engine cradle bolts
     
    Vehicle Speed Sensor (VSS) from the right control arm
     

  6.  
  7. Lower the cradle to gain access for the crankshaft damper puller.
  8.  
  9. Remove or disconnect the following:
    NOTE
    The front cover gasket is reusable as long as it is not damaged.



    Crankshaft balancer
     
    Drive belt tensioner and idler pulley
     
    Front cover and gasket
     

  10.  
  11. Partially drain the cooling system.
    NOTE
    Continue moving the cover upward and pivoting so that the edge of the cover closely follows the left edge of the intake manifold cover. The gasket is reusable as long as it is not damaged.


    NOTE
    Access the upper chain guide mounting bolt through the hole in the cylinder head capped with the plastic plug.



    Upper radiator hose at the water crossover
     
    Spark plug wires
     
    Right side fan
     
    Battery cable at the alternator
     
    Spark plug wires
     
    Wiring harness at the rocker arm cover
     
    Positive Crankcase Ventilation (PCV) tube from the rocker arm cover
     
    Right and left torque struts
     
    Battery cable retainer at the front of the rocker arm cover
     
    Ignition Control Module (ICM)
     
    Rocker arm cover by pivoting it around the water pump driveshaft
     



    Left side secondary chain tensioner
     
    Left side chain guide
     



    Secondary drive chain and sprockets
     

  12.  

To install:

Click image to see an enlarged view

Fig. Primary and secondary timing mark alignment-4.0L (VIN C) engine



Click image to see an enlarged view

Fig. Rotating tensioner release lever-4.0L (VIN C) engine



Click image to see an enlarged view

Fig. Locking the tensioner into position-4.0L (VIN C) engine


NOTE
Correct timing exists when the crankshaft and intermediate shaft sprocket timing marks are in alignment and all 4 camshaft drive pins are perpendicular (90 degrees) to the cylinder head surface.

  1. Assemble the left side secondary timing chain as follows:
    1. Route the timing chain over the intermediate sprocket teeth outer row.
    2.  
    3. Route the timing chain over the chain guide and install the exhaust camshaft sprocket so the LE (Left Head Exhaust) pin engages the sprocket notch.
      NOTE
      There should be no slack in the lower section of the timing chain and the camshaft drive pin must be perpendicular to the cylinder head face.

    4.  
    5. Install the intake camshaft sprocket into the chain so the sprocket notch LI (Left Head Intake) engages the camshaft and the camshaft drive pin remains perpendicular to the cylinder head face.
      NOTE
      A hex is cast into the camshafts behind the lobes for cylinder No. 2, so an open end wrench may be used to provide minor repositioning of the cams.

    6.  

  2.  
  3. Install or connect the following:

    Exhaust and intake camshaft sprockets, do not tighten the bolts
     
    Chain guide
     
    Camshaft sprocket bolts. Torque the bolts to 90 ft. lbs. (120 Nm).
     
    Chain tensioner. Torque the bolts to 18 ft. lbs. (25 Nm).
     
    Rocker arm cover. Torque the screws to 89 inch lbs. (10 Nm).
     
    ICM
     
    Battery cable retainer to the front of the rocker arm cover
     

  4.  
  5. Install the right and left torque struts and torque the bolts as follows:
    NOTE
    It is important during installation that the engine torque struts are not preloaded in their installed position. Adjustment is provided at the point the strut fastens to the core support bracket. Be sure this bolt is loose during assembly.

    1. Step 1: Strut bracket-to-cylinder head (M10) bolt: 35 ft. lbs. (50 Nm).
    2.  
    3. Step 2: Strut bracket-to-water manifold (M8) bolts: 20 ft. lbs. (25 Nm).
    4.  
    5. Step 3: Strut-to-core support bracket bolt: 45 ft. lbs. (60 Nm).
    6.  

  6.  
  7. Install or connect the following:

    PCV fresh air tube to the rocker arm cover
     
    Wiring harness to the cover
     
    Spark plug wires
     
    Battery cable at the alternator
     
    Right side fan
     
    Upper radiator hose to the water crossover
     
    Front cover with a new gasket. Torque the bolts to 89 inch lbs. (10 Nm).
     

  8.  
  9. Apply a dab of RTV to the split line between the upper and lower crankcase assemblies.
  10.  
  11. Install or connect the following:

    Drive belt idler pulley. Torque the bolt to 35 ft. lbs. (47 Nm).
     
    Drive belt tensioner. Torque the nut to 35 ft. lbs. (47 Nm).
     
    Crankshaft balancer. Lubricate the bolt threads with engine oil and torque the bolt to 44 ft. lbs. (60 Nm) then an additional 120 degree turn.
     
    VSS sensor
     
    Engine cradle. Torque the bolts to 75 ft. lbs. (102 Nm).
     
    Wheel well splash shields
     
    Wheels
     
    Exhaust Y-pipe to the converter. Torque the bolts to 20 ft. lbs. (25 Nm).
     
    Tower-to-tower brace
     
    Drive belt
     
    Negative battery cable
     

  12.  
  13. Refill the cooling system.
  14.  
  15. Start the engine and check for leaks.
  16.  

Primary Chain

The engine must be removed from the vehicle and supported on an engine stand.

  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Remove or disconnect the following:

    Engine
     
    Both secondary timing chains
     
    Primary timing chain tensioner
     
    Intermediate shaft sprocket
     
    Primary chain and sprocket assembly by sliding it off the shafts

    Click image to see an enlarged view

    Fig. Primary drive chain components-4.0L (VIN C) engine

     

  4.  

To install:

  1. Install or connect the following:
    NOTE
    If it is necessary to turn the crankshaft sprocket, the intermediate shaft sprocket will also have to be turned so the timing mark aligns with the crankshaft sprocket.



    Crankshaft sprocket, intermediate shaft sprocket and primary timing chain assembly
     



    Intermediate shaft sprocket bolt. Torque the bolt to 44 ft. lbs. (60 Nm).
     
    Primary timing chain tensioner bolts. Torque them to 18 ft. lbs. (25 Nm).
     
    Both secondary timing chains
     
    Engine
     

  2.  

Right Side Secondary Chain

NOTE
The secondary timing chains can be removed without removing the engine from the vehicle.

  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Remove or disconnect the following:

    Exhaust Y-pipe from the converter
     
    Tower-to-tower brace
     
    Ignition Control Module (ICM)
     
    Spark plug wires from the right bank
     
    Positive Crankcase Ventilation (PCV) valve
     
    Purge canister solenoid from the rear of the cover
     
    Rocker arm cover
     

  4.  
  5. Safely support the front of the engine cradle.
  6.  
  7. Remove or disconnect the following:

    2 mounting bolts at the front of the cradle
     
    Right and left torque struts
     

  8.  
  9. Lower the engine cradle (or raise the vehicle) to provide clearance at the rear of the engine compartment.
  10.  
  11. Remove or disconnect the following:
    NOTE
    Access the upper chain guide mounting bolt through the hole in the cylinder head capped with the plastic plug.



    Left side secondary timing chain
     
    Right side secondary chain tensioner
     
    Right side chain guide
     



    Right side camshaft sprocket bolts and camshaft sprockets
     
    Secondary drive chain
     

  12.  

To install:


NOTE
Correct timing exists when the crankshaft and intermediate shaft sprocket timing marks are in alignment and all 4 camshaft drive pins are perpendicular (90 degrees) to the cylinder head surface.

  1. Install the secondary timing chain guide.
  2.  
  3. Assemble the right side secondary timing chain as follows:
    1. Over the intermediate shaft sprocket inner row of teeth.
    2.  
    3. Over the chain guide.
    4.  
    5. Exhaust camshaft sprocket so the RE (Right Head Exhaust) pin engages the sprocket notch.
      NOTE
      There should be no slack in the lower section of the timing chain and the camshaft drive pin must be perpendicular to the cylinder head face.

    6.  
    7. Intake camshaft sprocket into the chain so the sprocket notch RI (Right Head Intake) engages the camshaft and the camshaft drive pin remains perpendicular to the cylinder head face.
      NOTE
      A hex is cast into the camshafts behind the lobes for cylinder No. 1, so an open end wrench may be used to provide minor repositioning of the cams.

    8.  

  4.  
  5. Install or connect the following:

    Exhaust and intake camshaft sprockets, do not tighten
     
    Timing chain tensioner. Torque the bolts to 18 ft. lbs. (25 Nm).
     
    Camshaft sprocket bolts. Torque the bolts to 90 ft. lbs. (120 Nm).
     
    Left side secondary timing chain
     
    Torque struts
     
    Engine cradle. Torque the bolts to 75 ft. lbs. (102 Nm).
     
    Rocker arm cover. Torque the screws to 84 inch lbs. (10 Nm).
     
    Purge canister solenoid
     
    PCV valve
     
    Spark plug wires
     
    ICM
     
    Tower to tower brace
     
    Exhaust Y-pipe to the converter. Torque the bolts to 20 ft. lbs. (25 Nm).
     

  6.  

3.5L Engine
Primary Chain
  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Remove or disconnect the following:

    Negative battery cable
     
    Rocker arm covers
     

  4.  
  5. Rotate the crankshaft so the No. 1 piston is at Top Dead Center (TDC) and the flats on the rear of the camshafts are parallel with the camshaft cover sealing surface.
  6.  
  7. Install camshaft holding fixtures on both sets of camshafts.
  8.  
  9. Drain the cooling system.
  10.  
  11. Remove or disconnect the following:

    Front diagonal brace
     
    Battery and tray
     
    Washer and coolant reservoirs
     
    Underhood accessory wiring junction block and move it aside
     
    Drive belt
     
    Power steering pump pulley
     
    Idler pulley
     
    Belt tensioner
     
    Water pump
     

  12.  
  13. Support the engine cradle
  14.  
  15. Remove or disconnect the following:
    NOTE
    Note that each plug has an O-ring.


    NOTE
    Remove the lower bolt allowing the tensioner to swing down and expand.



    Right side engine cradle bolts and lower the cradle
     
    Crankshaft balancer
     
    Front cover
     
    Lift bracket from the front of the engine
     
    Camshaft Position (CMP) sensor
     
    Sprocket bolt from the exhaust camshaft on the right cylinder head to allow for clearance of the chain guide
     
    4 chain guide access plugs from the cylinder heads
     



    Primary chain tensioner
     



    Primary chain tensioner shoe by removing the bolt, pushing the guide downward slightly and pulling it up through the cylinder head
     
    Primary chain from the right camshaft, allowing it to fall into the oil pump area
     
    Primary chain

    Click image to see an enlarged view

    Fig. Primary timing chain alignment marks-3.5L engine



    Click image to see an enlarged view

    Fig. Compressing the primary chain tensioner-3.5L engine



    Click image to see an enlarged view

    Fig. Apply RTV sealant to the 3 areas indicated before installing the front cover and gasket-3.5L engine

     

  16.  

To install:

  1. Rotate the crankshaft so the No. 1 piston is at TDC and the mark on the crankshaft is at the 4 o-clock position.
  2.  
  3. Rotate the balance shaft so the timing mark is at the 5 o-clock position.
    NOTE
    Be sure the painted links are facing the front of the engine.

  4.  
  5. Install the timing chain on the sprockets.
  6.  
  7. Center the mark on the left intake camshaft sprocket between the 2 painted links.
  8.  
  9. Lift the chain onto the right intake camshaft sprocket. While doing this, align the marks on the balance shaft and crankshaft sprockets with the painted marks on the chain.
  10.  
  11. Verify that all of the timing marks are aligned.
  12.  
  13. Install the primary chain tensioner shoe. Torque the bolt to 22 ft. lbs. (30 Nm).
  14.  
  15. Compress the primary chain tensioner using the following steps:
    1. Rotate the ratchet release lever counterclockwise and hold it.
    2.  
    3. Press the tensioner shoe in and hold it.
    4.  
    5. Release the ratchet lever and slowly release the pressure on the shoe.
    6.  
    7. Insert a pin through the hole in the lever as the lever moves to the first click. The ratchet should hold the shoe in the compressed position.
      NOTE
      Be sure the lever on the tensioner is facing you when installed.

    8.  

  16.  
  17. Install or connect the following:

    Primary chain tensioner. Torque the bolts to 18 ft. lbs. (25 Nm); then remove the chain tensioner pin.
     
    4 chain guide access plugs. Torque the plugs to 44 inch lbs. (5 Nm).
     
    Front engine lift bracket. Torque the hex head bolt to 37 ft. lbs. (50 Nm) and the internal drive bolt to 18 ft. lbs. (25 Nm).
     
    CMP sensor. Torque the bolts to 80 inch lbs. (9 Nm).
     

  18.  
  19. Remove the camshaft holding tools.
  20.  
  21. Place a small bead of RTV sealant on the 3 areas indicated in the diagram.
  22.  
  23. Install or connect the following:

    Front cover with a new gasket. Torque the bolts to 124 inch lbs. (14 Nm) and the coolant drain plug to 89 inch lbs. (10 Nm).
     
    Crankshaft balancer. Torque the bolt to 37 ft. lbs. (50 Nm); then an additional 120 degree turn.
     

  24.  
  25. Raise the engine cradle and install new bolts. Torque the bolts to 133 ft. lbs. (180 Nm).
  26.  
  27. Coat the sub-frame bushings with rubber lubricant.
  28.  
  29. Install or connect the following:

    Water pump with a new gasket. Torque the bolts to 124 inch lbs. (14 Nm).
     
    Belt tensioner. Torque the bolts to 37 ft. lbs. (50 Nm).
     
    Idler pulley. Torque the bolt to 37 ft. lbs. (50 Nm).
     
    Power steering pump pulley
     
    Drive belt
     
    Underhood accessory wiring junction block
     
    Washer and coolant reservoirs
     
    Battery and tray
     
    Front diagonal brace
     
    Rocker arm covers. Torque the bolts to 80 inch lbs. (9 Nm).
     
    Negative battery cable
     

  30.  
  31. Refill the cooling system.
  32.  
  33. Refill the crankcase.
  34.  
  35. Start the engine and verify no leaks.
  36.  

Secondary Chain
  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Remove the rocker arm cover and install camshaft holding fixture J-42038.
  6.  
  7. Remove the camshaft sprocket bolts and install the timing chain holding fixture J-42042 on the cylinder head.
  8.  
  9. Remove or disconnect the following:

    Sprockets and chain
     
    Secondary timing sprocket and chain
     

  10.  

To install:

Click image to see an enlarged view

Fig. Correct sprocket alignment for the left secondary timing chain-3.5L engine



Click image to see an enlarged view

Fig. Correct sprocket alignment for the right secondary timing chain-3.5L engine

  1. Install or connect the following:

    Secondary timing chain on the sprockets, with the drive pins at the 12 o-clock positions
     
    Sprockets and chain assembly onto the camshafts, with the chain properly aligned on the tensioner
     

  2.  
  3. Remove the timing chain holding fixture
  4.  
  5. Install the sprocket bolts. Torque the bolts to 18 ft. lbs. (25 Nm); then an additional 45 degree turn.
  6.  
  7. Remove the camshaft holding fixture.
  8.  
  9. Install or connect the following:

    Rocker arm cover
     
    Negative battery cable
     

  10.  

 
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