Inspection Procedure

Imperfections of the reluctor ring teeth may effect OBD II system performance.

1. Perform a visual inspection of the crankshaft for damage.
2. Inspect the crankshaft position reluctor ring lobes for damage.
3. Inspect the crankshaft journals for wear (1).

   Journals should be smooth with no signs of scoring, wear, or damage.

4. Inspect the crankshaft journals for grooves or scoring (2).
5. Inspect the crankshaft journals for scratches or wear (3).
6. Inspect the crankshaft journals for pitting or imbedded bearing material (4).
   Fig 1: Inspecting Crankshaft Journals

   Courtesy of GENERAL MOTORS CORP.
7. Inspect the crankshaft key (1), keyway (2), and threaded hole (3) for damage.
   Fig 2: Inspecting Crankshaft Key, Keyway, And Threaded Hole

   Courtesy of GENERAL MOTORS CORP.
8. Measure the crankpins for the out-of-round.
9. Measure the crankpins for taper.
   Fig 3: Measuring Crankpins For Out-Of-Round And Taper

   Courtesy of GENERAL MOTORS CORP.
10. Measure the crankshaft thrust wall width.

    A crankshaft with a thrust wall width in excess of 26.2 mm (1.0315 in) must be replaced.

    Fig 4: Measuring Crankshaft Thrust Wall Width

    Courtesy of GENERAL MOTORS CORP.
11. Measure the crankshaft runout.

    Use wooden V blocks or a fixture to support the crankshaft on the front and rear journals.

12. Use the J 7872  in order to measure the crankshaft runout at the front and rear intermediate journals.
13. Use the J 7872  in order to measure the runout of the crankshaft rear flange.
14. Use the J 7872  in order to measure the runout of the crankshaft position reluctor ring. Reluctor ring runout should be measured 1.0 mm (0.04 in) below the ring teeth.

    If the reluctor ring has runout in excess of 0.7 mm (0.028 in), replace the crankshaft.

    Fig 5: Measuring Crankshaft Runout

    Courtesy of GENERAL MOTORS CORP.
15. Inspect crankshaft bearings for craters or pockets. Flattened sections on the bearing halves also indicate fatigue.
    Fig 6: Inspecting Crankshaft Bearings For Craters Or Pockets

    Courtesy of GENERAL MOTORS CORP.
16. Inspect the crankshaft bearings for excessive scoring or discoloration.
17. Inspect the crankshaft bearings for dirt or debris imbedded into the bearing material.
    Fig 7: Inspecting Crankshaft Bearings For Dirt Or Debris Imbedded Into Bearing Material

    Courtesy of GENERAL MOTORS CORP.
18. Inspect the crankshaft bearings for improper seating indicated by bright, polished sections of the bearing.

    If the lower half of the bearing is worn or damaged, both upper and lower halves should be replaced.

    Generally, if the lower half is suitable for use, the upper half should also be suitable for use.

    Fig 8: Inspecting Crankshaft Bearings For Improper Seating

    Courtesy of GENERAL MOTORS CORP.