GM Service Manual Online
For 1990-2009 cars only

Tools Required

    • OTC 1726 (KM-412) Engine Overhaul Stand or equivalent
    • J 45059 Angle Meter
    • J 36972 or KM-635 Crankshaft Rear Oil Seal Installer
    • KM-535 Installer

Disassembly Procedure

    Caution: Refer to Safety Glasses Caution in the Preface section.


    Object Number: 1241261  Size: SH

    Notice: Use extreme care when installing the camshaft not to nick, scratch, or damage the camshaft lobes or bearing surfaces.

  1. Remove the engine. Refer to Engine Replacement .
  2. Remove the flywheel or the flexible plate bolts.
  3. Remove the flywheel or the flexible plate.

  4. Object Number: 1241262  Size: SH
  5. Remove the crankshaft rear oil seal.
  6. Mount the engine assembly on the OTC 1726 .

  7. Object Number: 1263767  Size: SH
  8. Remove the front timing belt cover bolts.
  9. Remove the front timing belt cover.
  10. Remove the crankshaft pulley bolts.
  11. Remove the crankshaft pulley.

  12. Object Number: 1252168  Size: SH
  13. Loosen the timing belt automatic tensioner bolt.
  14. Rotate the timing belt automatic tensioner hex-key clockwise to release the tension.
  15. Remove the timing belt idler pulley nuts.
  16. Remove the timing belt idler pulleys.
  17. Remove the timing belt.
  18. Remove the engine mount retaining bolt.
  19. Remove the engine mount.

  20. Object Number: 1263768  Size: SH
  21. Disconnect the crankcase breather tubes from the valve cover.
  22. Remove the spark plug cover bolts.
  23. Remove the spark plug cover.
  24. Disconnect the ignition wires from the spark plugs.
  25. Remove the valve cover bolts.
  26. Remove the valve cover washers.
  27. Remove the valve cover and the valve cover gasket.

  28. Object Number: 1263772  Size: SH

    Notice: Use extreme care when installing the camshaft not to nick, scratch, or damage the camshaft lobes or bearing surfaces.

  29. While holding the intake camshaft firmly in place, remove the intake camshaft bolt.
  30. Remove the intake camshaft gear.
  31. While holding the exhaust camshaft firmly in place, remove the exhaust camshaft bolt.
  32. Remove the exhaust camshaft gear.

  33. Object Number: 1252132  Size: SH
  34. Remove the crankshaft timing belt gear.

  35. Object Number: 1263771  Size: SH
  36. Remove the rear timing belt cover bolts and cover.

  37. Object Number: 1241263  Size: SH
  38. Rotate the engine on the OTC 1726  (1).

  39. Object Number: 1241264  Size: SH
  40. Remove the oil pan retaining bolts.
  41. Remove the oil pan.
  42. Remove the oil pump/pickup tube bolts.
  43. Remove the oil pump/pickup tube.
  44. Remove the lower block support bracket/splash shield bolts.
  45. Remove the splash shield.
  46. Remove the lower block support bracket bolts.
  47. Remove the lower block support bracket.

  48. Object Number: 1263775  Size: SH
  49. Remove the oil pump retaining bolts.
  50. Remove the oil pump.

  51. Object Number: 1256127  Size: SH
  52. Mark the order of the connecting rod bearing caps.
  53. Remove the connecting rod bearing cap bolts for all of the pistons.
  54. Remove the connecting rod bearing caps and the lower connecting rod bearings.

  55. Object Number: 1256128  Size: SH
  56. Mark the order of the crankshaft bearing caps.
  57. Remove the crankshaft bearing cap bolts.
  58. Remove the crankshaft bearing caps and the lower crankshaft bearings.
  59. Remove the crankshaft.
  60. Caution: Refer to Safety Glasses Caution in the Preface section.

  61. Clean any necessary parts.

Assembly Procedure


    Object Number: 1256129  Size: SH
  1. Coat the crankshaft bearings with engine oil.
  2. If replacing the crankshaft, transfer the pulse pickup sensor disc to the new crankshaft.
  3. Tighten
    Tighten the pulse pickup sensor disc to 13 N·m (115 lb in).


    Object Number: 1241789  Size: SH
  4. Install the crankshaft.
  5. Install the lower crankshaft bearings in the bearing caps.
  6. Inspect the crankshaft end play with the crankshaft bearings installed.
  7. Check for permissible crankshaft end play. Refer to Engine Mechanical Specifications .

  8. Object Number: 1241794  Size: SH
  9. With the crankshaft mounted on the front and rear crankshaft bearings, check the middle crankshaft journal for permissible out-of-round, runout. Refer to Engine Mechanical Specifications .

  10. Object Number: 1241455  Size: SH

    Important: Grease the crankshaft journals and lubricate the crankshaft bearings slightly so that the plastic gaging thread does not tear when the crankshaft bearing caps are removed.

  11. Measure all of the crankshaft bearing clearances using a commercially available plastic gaging, ductile plastic threads.
  12. Cut the plastic gaging threads (1) to the length of the bearing width. Lay them axially between the crankshaft journals and the crankshaft bearings.
  13. Notice: Refer to Fastener Notice in the Preface section.

  14. Install the crankshaft bearing caps and the bolts.
  15. Tighten
    Tighten the crankshaft bearing cap bolts to 50 N·m (37 lb ft). Using the J 45059 or the KM-470-B (1), tighten the bolt an additional turn of 45 degrees plus 15 degrees.


    Object Number: 1241457  Size: SH
  16. Remove the crankshaft bearing cap bolts and the caps.
  17. Measure the width of the flattened plastic thread (1) of the plastic gaging using the scale printed on the plastic gaging package. Plastic gaging is available for different tolerance ranges.
  18. Inspect the bearing clearance for permissible tolerance ranges. Refer to Engine Mechanical Specifications .

  19. Object Number: 1241797  Size: SH
  20. Apply a bead of adhesive sealing compound to the grooves of the crankshaft bearing caps.
  21. Install the crankshaft bearing caps to the engine block.
  22. Tighten the crankshaft bearing caps using new bolts.
  23. Tighten
    Tighten the crankshaft bearing cap bolts to 50 N·m (37 lb ft) using a torque wrench. Using the J 45059 or the KM-470-B  (1) , tighten the bolts an additional turn of 45 degrees, plus another turn of 15 degrees.


    Object Number: 1241455  Size: SH

    Important: Grease the connecting rod journals and lubricate the connecting rod bearings slightly so that the plastic gaging thread does not tear when the connecting rod bearing caps are removed.

  24. Measure all of the connecting rod bearing clearances using a commercially available plastic gaging, ductile plastic threads.
  25. Cut the plastic gaging threads (1) to the length of the connecting rod bearing width. Lay them axially between the connecting rod journals and the connecting rod bearings.
  26. Install the connecting rod bearing caps.
  27. Tighten
    Tighten the connecting rod bearing cap bolts to 35 N·m (26 lb ft) using a torque wrench. Use the J 45059 or the KM-470-B to tighten the connecting rod bearing cap bolts to plus 45 degrees plus 15 degrees.


    Object Number: 1241457  Size: SH
  28. Remove the connecting rod bearing caps.
  29. Measure the width of the flattened plastic thread (1) of the plastic gaging using the scale printed on the plastic gaging package. Plastic gaging is available for different tolerance ranges.
  30. Inspect the bearing clearance for permissible tolerance ranges. Refer to Engine Mechanical Specifications .

  31. Object Number: 1241750  Size: SH
  32. Install the connecting rod bearing caps to the connecting rods.
  33. Tighten the connecting rod bearing caps using new bolts.
  34. Tighten
    Tighten the connecting rod bearing cap bolts to 35 N·m (26 lb ft) using a torque wrench. Use the J 45059 or the KM-470-B  (1) to tighten the connecting rod cap bolts plus 45 degrees plus 15 degrees.


    Object Number: 1263775  Size: SH
  35. Install the oil pump.
  36. Install the oil pump retaining bolts.
  37. Tighten
    Tighten the oil pump retaining bolts to 10 N·m (89 lb in).


    Object Number: 1256130  Size: SH
  38. Install engine block lower support bracket and the bolts.
  39. Tighten
    Tighten the engine block lower support bracket bolts to 35 N·m (26 lb ft).

  40. Install the lower block support bracket splash shield and the bolts.
  41. Tighten
    Tighten the lower block support bracket splash shield bolts to 35 N·m (26 lb ft).

  42. Install the oil pump/pickup tube.
  43. Install the oil pump/pickup tube bolts.
  44. Tighten
    Tighten the oil pump/pickup tube bolts to 8 N·m (71 lb in).

  45. Install the oil pickup tube support bracket bolts.
  46. Tighten
    Tighten the support bracket to 10 N·m (89 lb ft).


    Object Number: 1252144  Size: SH
  47. Coat the new oil pan gasket with the sealant.
  48. Install the oil pan gasket to the oil pan.
  49. Install the oil pan.
  50. Install the oil pan retaining bolts.
  51. Tighten
    Tighten the oil pan retaining bolts to 10 N·m (89 lb in).


    Object Number: 1241263  Size: SH
  52. Rotate the engine on the OTC 1726  (1).

  53. Object Number: 1256131  Size: SH
  54. Install the rear timing belt cover.
  55. Install the rear timing belt cover bolts.
  56. Tighten
    Tighten the rear timing belt cover bolts to 6 N·m (33 lb in).

  57. Install the crankshaft timing belt drive gear and the bolt using the J 45059 .
  58. Tighten
    Tighten the crankshaft timing belt drive gear bolt to 130 N·m (96 lb ft) + 40 degrees using the J 45059 or the KM-470-B  (1).

  59. Install the engine mount and the retaining bolts.
  60. Tighten
    Tighten the engine mount retaining bolts to 60 N·m (44 lb ft).


    Object Number: 1252168  Size: SH
  61. Install the timing belt automatic tensioner.
  62. Install the timing belt automatic tensioner bolts.
  63. Tighten
    Tighten the timing belt automatic tensioner bolts to 25 N·m (18 lb ft).

  64. Install the timing belt idler pulley.
  65. Install the timing belt idler pulley nuts.
  66. Tighten
    Tighten the timing belt idler pulley nuts to 25 N·m (18 lb ft).


    Object Number: 1263772  Size: SH
  67. Install the intake camshaft gear.
  68. Install the intake camshaft gear bolt while holding the intake camshaft firmly in place.
  69. Tighten
    Tighten the intake camshaft gear bolt to 50 N·m (37 lb ft) plus 60 degrees and 15 degrees.

  70. Install the exhaust camshaft gear.
  71. Install the exhaust camshaft gear bolt while holding the exhaust camshaft firmly in place.
  72. Tighten
    Tighten the exhaust camshaft gear bolt to 50 N·m (37 lb ft) plus 60 degrees and 15 degrees.


    Object Number: 1263768  Size: SH
  73. Install the timing belt. Refer to Timing Belt Replacement .
  74. Adjust the timing belt tension. Refer to Timing Belt Inspection .
  75. Apply a small amount of gasket sealant to the corners of the front camshaft caps and to the top of the rear valve cover to the cylinder head seal.
  76. Install the valve cover and the valve cover gasket.
  77. Install the valve cover washers.
  78. Install the valve cover bolts.
  79. Tighten
    Tighten the valve cover bolts to 8 N·m (71 lb in).


    Object Number: 1252120  Size: SH
  80. Connect the ignition wires to the spark plugs.
  81. Install the spark plug cover.
  82. Install the spark plug cover bolts.
  83. Tighten
    Tighten the spark plug cover bolts to 3 N·m (27 lb in).

  84. Connect the crankcase breather tube to the valve cover.
  85. Install the front timing belt cover.
  86. Install the front timing belt cover bolts.
  87. Tighten
    Tighten the front timing belt cover bolts to 6 N·m (53 lb in).

  88. Install the engine lifting device.
  89. Remove the engine from the OTC 1726 .

  90. Object Number: 1241798  Size: SH
  91. Install a new crankshaft rear oil seal using the J 36972  (1) or KM-535 .

  92. Object Number: 1256132  Size: SH
  93. Install the flywheel or flexible plate.
  94. Install the flywheel or the flexible plate bolts. Tighten the flywheel or flexible plate bolt in the following order:
  95. Tighten

        • Tighten the flywheel bolts to 65 N·m (48 lb ft) + 30 degrees + 15 degrees.
        • Flexible plate bolts to 65 N·m (48 lb ft).
  96. Install the engine. Refer to Engine Replacement .