Cherokee, Grand Cherokee, 1999-2005

Timing Chain Cover, Chain, Sprockets, & Seal

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Removal & Installation



3.7L Engines
  1. Before servicing the vehicle, please familiarize yourself with safety procedures.
  2.  
  3. Disconnect the battery negative cable.
  4.  
  5. Drain cooling system.
  6.  
  7. Remove electric cooling fan and fan shroud assembly.
  8.  
  9. Remove radiator fan.
  10.  
  11. Rotate engine until timing mark on crankshaft damper aligns with TDC mark on timing chain cover.
  12.  
  13. Make sure the camshaft sprocket -V6- marks are at the 12 o-clock position (No. 1 TDC exhaust stroke).
  14.  
  15. Remove power steering pump.
  16.  
  17. Remove access plugs from left and right cylinder heads for access to chain guide fasteners.
  18.  
  19. Remove the oil fill housing to gain access to the right side tensioner arm fastener.
  20.  
  21. Disconnect both heater hoses at timing cover.
  22.  
  23. Disconnect lower radiator hose at engine.
  24.  
  25. Remove accessory drive belt tensioner assembly.
  26.  
  27. Remove crankshaft damper.
  28.  
  29. Remove the generator.
  30.  
  31. Remove A/C compressor.
    WARNING
    The 3.7L engine uses an anaerobic sealer instead of a gasket to seal the front cover to the engine block, from the factory. For service, Mopar° Grey Engine RTV sealant must be substituted.


    NOTE
    It is not necessary to remove the water pump for timing cover removal.

  32.  
  33. Remove the bolts holding the timing cover to engine block.
  34.  
  35. Remove the timing cover.
  36.  
  37. Collapse and pin primary chain tensioner.
    WARNING
    Plate behind left secondary chain tensioner could fall into oil pan. Therefore, cover pan opening.

  38.  
  39. Remove secondary chain tensioners.
  40.  
  41. Remove camshaft position sensor.
    WARNING
    Care should be taken not to damage camshaft target wheel. Do not hold target wheel while loosening or tightening camshaft sprocket. Do not place the target wheel near a magnetic source of any kind. A damaged or magnetized target wheel could cause a vehicle no start condition.


    WARNING
    Do not forcefully rotate the camshafts or crankshaft independently of each other. Damaging intake valve to piston contact will occur. Ensure negative battery cable is disconnected to guard against accidental starter engagement.

  42.  
  43. Remove left and right camshaft sprocket bolts.
  44.  
  45. While holding the left camshaft steel tube with Special Tool 8428 Camshaft Wrench, remove the left camshaft sprocket. Slowly rotate the camshaft approximately 5 degrees clockwise to a neutral position.
  46.  
  47. While holding the right camshaft steel tube with Special Tool 8428 Camshaft Wrench, remove the right camshaft sprocket.
  48.  
  49. Remove idler sprocket assembly bolt.
  50.  
  51. Slide the idler sprocket assembly and crank sprocket forward simultaneously to remove the primary and secondary chains.
  52.  
  53. Remove both pivoting tensioner arms and chain guides.
  54.  
  55. Remove primary chain tensioner.
  56.  

To install:

  1. Using a vise, lightly compress the secondary chain tensioner piston until the piston step is flush with the tensioner body. Using a pin or suitable tool, release ratchet pawl by pulling pawl back against spring force through access hole on side of tensioner. While continuing to hold pawl back, push ratchet device to approximately 2mm from the tensioner body. Install Special Tool 8514 lock pin into hole on front of tensioner. Slowly open vise to transfer piston spring force to lock pin.
  2.  
  3. Position primary chain tensioner over oil pump and insert bolts into lower two holes on tensioner bracket. Tighten bolts to 250 inch lbs. (28 Nm).
  4.  
  5. Install right side chain tensioner arm. Install Torx® bolt. Tighten bolt to 250 inch lbs. (28 Nm).
    WARNING
    The silver bolts retain the guides to the cylinder heads and the black bolts retain the guides to the engine block.

  6.  
  7. Install the left side chain guide. Tighten the bolts to 250 inch lbs. (28 Nm).
  8.  
  9. Install left side chain tensioner arm, and Torx® bolt. Tighten bolt to 250 inch lbs. (28 Nm).
  10.  
  11. Install the right side chain guide. Tighten the bolts to 250 inch lbs. (28 Nm).
  12.  
  13. Install both secondary chains onto the idler sprocket. Align two plated links on the secondary chains to be visible through the two lower openings on the idler sprocket (4 o-clock and 8 o-clock). Once the secondary timing chains are installed, position special tool 8429 to hold chains in place for installation.
  14.  
  15. Align primary chain double plated links with the timing mark at 12 o-clock on the idler sprocket. Align the primary chain single plated link with the timing mark at 6 o-clock on the crankshaft sprocket.
  16.  
  17. Lubricate idler shaft and bushings with clean engine oil.
    NOTE
    The idler sprocket must be timed to the counterbalance shaft drive gear before the idler sprocket is fully seated.

  18.  
  19. Install all chains, crankshaft sprocket, and idler sprocket as an assembly. After guiding both secondary chains through the block and cylinder head openings, affix chains with an elastic strap or equivalent. This will maintain tension on chains to aid in installation. Align the timing mark on the idler sprocket gear to the timing mark on the counterbalance shaft drive gear, then seat idler sprocket fully. Before installing idler sprocket bolt, lubricate washer with oil, and tighten idler sprocket assembly retaining bolt to 25 ft. lbs. (34 Nm).
    NOTE
    It will be necessary to slightly rotate camshafts for sprocket installation.

  20.  
  21. Align left camshaft sprocket -L- dot to plated link on chain.
  22.  
  23. Align right camshaft sprocket -R- dot to plated link on chain.
    WARNING
    Remove excess oil from the camshaft sprocket bolt. Failure to do so can result in over torque of bolt resulting in bolt failure.

  24.  
  25. Remove Special Tool 8429, then attach both sprockets to camshafts. Remove excess oil from bolts, then install sprocket bolts, but do not tighten at this time.
  26.  
  27. Verify that all plated links are aligned with the marks on all sprockets and the -V6- marks on camshaft sprockets are at the 12 o-clock position.
    WARNING
    Ensure the plate between the left secondary chain tensioner and block is correctly installed.

  28.  
  29. Install both secondary chain tensioners. Tighten bolts to 250 inch lbs. (28 Nm).
    NOTE
    Left and right secondary chain tensioners are not common.

  30.  
  31. Remove all locking pins from tensioners.
    WARNING
    After pulling locking pins out of each tensioner, do not manually extend the tensioner(s) ratchet. Doing so will over tension the chains, resulting in noise and/or high timing chain loads.

  32.  
  33. Using Special Tool 6958, Spanner with Adaptor Pins 8346, tighten left camshaft sprocket bolts to 90 ft. lbs. (122 Nm).
  34.  
  35. Using Special Tool 6958, Spanner with Adaptor Pins 8346, tighten right camshaft sprocket bolts to 90 ft. lbs. (122 Nm).
  36.  
  37. Rotate engine two full revolutions. Verify timing marks are at the follow locations:

    primary chain idler sprocket dot is at 12 o-clock
     
    primary chain crankshaft sprocket dot is at 6 o-clock
     
    secondary chain camshaft sprockets -V6- marks are at 12 o-clock
     
    counterbalance shaft drive gear dot is aligned to the idler sprocket gear dot
     

  38.  
  39. Lubricate all three chains with engine oil.
  40.  
  41. After installing all chains, it is recommended that the idler gear end play be checked. The end play must be within 0.10-0.25mm (0.004-0.010 in.). If not within specification, the idler gear must be replaced.
    WARNING
    Do not use oil based liquids to clean timing cover or block surfaces. Use only rubbing alcohol, along with plastic or wooden scrapers. Use no wire brushes or abrasive wheels or metal scrapers, or damage to surfaces could result.

  42.  
  43. Clean timing chain cover and block surface using rubbing alcohol.
    WARNING
    The 3.7L uses a special anaerobic sealer instead of a gasket to seal the timing cover to the engine block, from the factory. For service repairs, Mopar® Engine RTV must be used as a substitute.

  44.  
  45. Inspect the water passage O-rings for any damage, and replace as necessary.

    Click image to see an enlarged view

    Fig. Front cover sealant application-3.7L engine

  46.  
  47. Apply Mopar® Engine RTV sealer to front cover as shown using a 3 to 4mm thick bead.
  48.  
  49. Install cover. Tighten fasteners in sequence as shown in to 43 ft. lbs. (58 Nm).
  50.  
  51. Install crankshaft damper.
  52.  
  53. Install the A/C compressor.
  54.  
  55. Install the generator.
  56.  
  57. Install accessory drive belt tensioner.
  58.  
  59. Install radiator upper and lower hoses.
  60.  
  61. Install both heater hoses.
  62.  
  63. Install radiator fan.
  64.  
  65. Install cylinder head covers.
    NOTE
    Before installing threaded plug in right cylinder head, the plug must be coated with sealant to prevent leaks.

  66.  
  67. Coat the large threaded access plug with Mopar® Thread Sealant with Teflon, then install into the right cylinder head and tighten to 60 ft. lbs. (81 Nm).
  68.  
  69. Install the oil fill housing.
  70.  
  71. Install access plug in left cylinder head.
  72.  
  73. Install power steering pump.
  74.  
  75. Fill cooling system.
  76.  
  77. Connect negative cable to battery.
  78.  

 
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