GM Northstar crankshaft rear main seal installation
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Tools Required

  • EN-48072 Sealant Applicator
  • J 45930-A Crankshaft Rear Oil Seal Installer

Important Notes

  • The EN-48072 must be used to ensure even application of the sealant in the bore and to prevent blockage of the drain back hole.
  • Ensure components that are being sealed with RTV sealant are assembled within 20 minutes. Components assembled after the RTV sealant has skinned-over, approximately 20 minutes, will not bond properly.
  • Although originally equipped with a lip-style crankshaft rear oil seal, engines built from March 1, 1996 and thru 1999 should use the cassette-style crankshaft rear oil seal.

Procedure

  1. Ensure the engine block where the crankshaft rear oil seal is installed is a deep bore (1).
    Northstar rms00.gif
    • A deep bore of approximately 15 mm (0.5906 in) was used on engines from March 1, 1996 and later.
    • A shallow bore of approximately 8 mm (0.3150 in) was used on engines from 1993 thru February 29, 1996. This block would use a lip-style crankshaft rear oil seal and the J 38817-A for installation.
  2. Inspect the engine block bore (1) and the crankshaft flange (2) for the damage. Repair or replace any damaged components.
    Northstar rms01.gif
  3. Ensure the oil drain-back hole (1) is clear of debris using a wire or an unbound plastic tie wrap (2).
    Northstar rms02.gif
  4. Clean the bore in the block with cleaner solvent GM P/N 12378392 or 12346139 (Canadian P/N 88901247).
    Northstar rms03.gif
    • In order to ensure proper bonding of the sealant the bore must be clean and dry.
  5. Remove the proper sized bolts from the J 45930-A . Use the bolts (2) 8 mm or the bolts (3) 11 mm.
    Northstar rms04.gif
    • Northstar engines 2005 and older have an 8 x 1.25 mm flywheel/flexplate crankshaft bolt hole thread. Northstar engines 2006 and later have an 11 x 1.5 mm flywheel/flexplate crankshaft bolt hole thread.
  6. Install the EN-48072 pilot base onto the crankshaft. The hub on the crankshaft will fit into the recess on the inboard side of the EN-48072 pilot base.
    Northstar rms05.gif
    • Northstar engines 2005 and older have an 8 x 1.25 mm flywheel/flexplate crankshaft bolt hole thread. Northstar engines 2006 and later have an 11 x 1.5 mm flywheel/flexplate crankshaft bolt hole thread.
  7. Use the proper bolts from the J 45930-A to retain the EN-48072 pilot base in place.
    Northstar rms06.gif
  8. Install the EN-48072 applicator housing over the EN-48072 pilot base. Ensure the EN-48072 applicator housing bottoms in the bore of the block
    Northstar rms07.gif
  9. Apply the sealant GM P/N 12378521 (Canadian P/N 88901148) to the bore outer diameter in the block. Ensure the sealant does not block the drain hole.
    Northstar rms08.gif
    • Important: The sealant must not block the drain back hole. Blockage of the drain back hole can lead to oil leakage.
  10. Using a suitable tool spread the sealant within the bore to ensure an even coating across the bore.
    Northstar rms09.gif
    • Apply steady even pressure to the EN-48072 applicator housing.
  11. Using both hands, slowly and evenly, pull the EN-48072 applicator housing out of the bore and remove it from the EN-48072 pilot base.
    Northstar rms10.gif
    • In order to apply an even coat of the sealant do not twist or turn the EN-48072 applicator housing as it is pulled away from the bottom of the bore.
  12. Remove the J 45930-A bolts from the EN-48072 pilot base.
    Northstar rms11.gif
  13. Remove the EN-48072 pilot base.
    Northstar rms12.gif
  14. Ensure that the sealant (1) is evenly spread across the bore of the block.
    Northstar rms13.gif
  15. Ensure the drain back hole (1) is clear of the sealant.
    Northstar rms14.gif
    Northstar drainback2.jpg
    • If this hole is not cleared the rear main seal may get blown out.
  16. Ensure the proper size of bolt (2) 8 mm or (3) 11 mm is being installed in the J 45930-A.
    Northstar rms15.gif
    • The cassette seal is installed onto the crankshaft with a press fit that requires over 135 Nm (100 lb ft) of force to remove or install. This high force requires the use of special tools to remove and install the seal. Use of any other tools during removal or installation can lead to damage to the seal or other components. An improperly installed or damaged seal can leak oil and can lead to engine damage. Use of the J 38817-A to install the cassette seal can damage the tool and cause improper seal installation and/or seal damage.
    • Beginning with the model year 2006 the flywheel/flexplate crankshaft bolt hole thread was changed from 8 x 1.25 mm to 11 x 1.5 mm. The J 45930-A will service the cassette seals installed on engines from March 1, 1996 to 2006. If a J 45930 is to be used on a 2006 or later engine the update kit, J 45930-10, must be used to convert the J 45930 to a J 45930-A .
    • Crankshaft rear oil seal and engine flywheel installation requires adequate space for installation. If the engine stand does not allow suitable space to use the J 45930-A install the crankshaft rear oil seal and engine flywheel with the engine properly supported on the floor or on a bench.
  17. Turn the center nut (1) of the J 45930-A until the center hub (2) protrudes approximately 15 mm (0.591 in) beyond the outer plate (3).
    Northstar rms16.gif
  18. Do not lubricate any part of the new cassette style crankshaft rear oil seal.
    Northstar rms17.gif
    • DO NOT use any lubricant in order to install the crankshaft rear oil seal. Do not use any lubricant on the coating pre-applied to the inner diameter of the crankshaft rear oil seal. The coating is a sealant that must not be contaminated. Do not use any lubricant on the outer diameter of the crankshaft rear oil seal. The sealant applied to the bore of the engine block will not properly bond to a lubricated crankshaft rear oil seal.
  19. Install the new cassette style crankshaft rear oil seal onto the center hub of the J 45930-A.
    Northstar rms18.gif
  20. Thread the two J 45930-A mounting bolts into the crankshaft flywheel bolt holes.
    Northstar rms19.gif
  21. Tighten the two mounting bolts until the J 45930-A is firmly mounted on the crankshaft.
    Northstar rms20.gif
  22. Install the new cassette style crankshaft rear oil seal by turning the nut of the J 45930-A until the drive portion of the J 45930-A bottoms against the crankcase.
    Northstar rms21.gif
  23. Loosen the center nut to release pressure on the crankcase.
    Northstar rms22.gif
  24. Loosen the two mounting bolts.
    Northstar rms23.gif
  25. Remove the J 45930-A from the crankshaft.
    Northstar rms24.gif
  26. Wipe off any excessive sealant from the block.
  27. Ensure the new cassette style crankshaft rear oil seal is installed properly.
    • The outer surface of the seal (3) should be 0.500-0.800 mm (0.0197-0.0315 in) (1) below the surface of the engine block (2).
    • The inner surface of the sleeve (6) should be 0.400-0.900 mm (0.0158-0.0354 in) (4) below the surface of the outer surface of the seal (5).
    • The installed seal and sleeve need to be parallel to the block by 0.000-0.500 mm (0.000-0.0197 in).
  28. Clean all tools to remove any residual sealant.