GM Service Manual Online
For 1990-2009 cars only

Inspection Procedure


    Object Number: 2018187  Size: SH
  1. Using a dial indicator and V-blocks, measure the circle runout as shown in the illustration.
  2. Maximum Circle Runout
    0.03 mm (0.0012 in)

  3. If the circle runout is greater than the maximum, replace the crankshaft.

  4. Object Number: 2018189  Size: SH
  5. Using a micrometer, measure the diameter of each main journal.
  6. Standard Diameter
    54.988 to 55.000 mm (2.1649 to 2.1654 in)

  7. If the diameter is not as specified, check the crankshaft oil clearance.
  8. Check each main journal for taper and distortion as shown in the illustration.
  9. Maximum Taper and Distortion
    0.003 mm (0.0001 in)

  10. If the taper and distortion are greater than the maximum, replace the crankshaft.

  11. Object Number: 2017301  Size: SH
  12. Using a micrometer, measure the diameter of each crank pin.
  13. Standard Diameter
    47.990 to 48.000 mm (1.8894 to 1.8898 in)

  14. If the diameter is not as specified, check the connecting rod oil clearance.
  15. Inspect each crank pin for taper and distortion as shown in the illustration.
  16. Maximum Taper and Distortion
    0.003 mm (0.0001 in)

  17. If the taper and distortion are greater than the maximum, replace the crankshaft.
  18. Install the main bearing cap.

  19. Object Number: 2018192  Size: SH

    Note: The thrust washer thickness is 1.93 to 1.98 mm (0.0760 to 0.0780 in).

  20. Using a dial indicator, measure the thrust clearance while prying the crankshaft back and forth with a screwdriver.
  21. Standard Thrust Clearance
    0.04 to 0.24 mm (0.0016 to 0.0095 in)

    Maximum Thrust Clearance
    0.30 mm (0.0118 in)

  22. If the thrust clearance is greater than the maximum, replace the thrust washers as a set.
  23. Check the crank journal and bearing for pitting and scratches.
  24. Install the crankshaft bearing.
  25. Place the crankshaft on the cylinder block.

  26. Object Number: 2018196  Size: SH
  27. Lay a strip of Plastigage across each journal.
  28. Note: A number is marked on each main bearing cap to indicate the installation position.

  29. Examine the front marks and numbers and install the bearing caps on the cylinder block.
  30. Note: Do not turn the crankshaft.

  31. Install the main bearing caps.
  32. Remove the main bearing caps.

  33. Object Number: 2018201  Size: MH

    Note: 

       • Remove the Plastigage completely after the measurement.
       • If replacing a bearing, select a new one with the same number. If the number of the bearing cannot be determined, calculate the correct bearing number by adding together the numbers imprinted on the cylinder block and crankshaft. Then select a new bearing with the calculated number. There are 4 sizes of standard bearings, marked 1, 2, 3 and 4 accordingly.
       • EXAMPLE: Cylinder block 3 + Crankshaft 5 = Total number 8 (Use bearing 3)

  34. Measure the Plastigage at its widest point.
  35. Standard Oil Clearance
    0.017 to 0.040 mm (0.0007 to 0.0016 in)

    Maximum Oil Clearance
    0.060 mm (0.0024 in)

  36. If the oil clearance is greater than the maximum, replace the crankshaft bearing. If necessary, replace the crankshaft.

  37. Object Number: 2018208  Size: SH
  38. Inspect crankshaft bearing cap set ring pin.
  39. Using vernier calipers, measure the tension portion diameter (a) of the bolts.
  40. Standard Diameter
    7.3 to 7.5 mm (0.287 to 0.295 in)

    Minimum Diameter
    7.2 mm (0.284 in)

  41. If the diameter is less than the minimum, replace the bolt.