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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1443 (Engine Mechanical - 4.2L (Ll8)) >> Repair Instructions >> Off-Vehicle Repair Instructions >> Engine Block Cleaning And Inspection

Engine Block Cleaning And Inspection

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Tools Required

    Fig 1: Checking Deck Surface For Flatness
    GM637756Courtesy of GENERAL MOTORS CORP.
  1. Clean the sealing material from all gasket mating surfaces.
  2. Clean the engine block with a cleaning solution.
  3. Flush the engine block with clean water.
  4. Clean the oil passages.
  5. Coat the cylinder bores and the machined surfaces with engine oil.
  6. Inspect the threaded holes. Clean the holes with a tap, if needed.
  7. Use a straight edge and a feeler gauge to check the deck surface for flatness. Carefully remove any minor irregularities. Replace the block if there is more than 0.08 mm (0.003 in) gap.
    8. Fig 2: Checking Engine Block Bores
    GM637764Courtesy of GENERAL MOTORS CORP.
  8. Replace the engine block if the bores are out of specification.
  9. Inspect the cylinder bores. Use J 8087  to measure the cylinder bore. See Special Tools and Equipment . Inspect the bores for the following conditions:
    • Wear
    • Taper
    • Runout
    • Ridging
    10. IMPORTANT: If the bore is worn beyond the limits, bore the cylinders and refit with the one oversized piston available.
  10. Leave sufficient material to allow finish honing when fitting the pistons.
    11. Fig 3: Checking Engine Block Flange Runout
    GM654710Courtesy of GENERAL MOTORS CORP.
  11. Inspect the oil pan rail for nicks. Use a flat file to remove an nicks.
  12. Inspect the front cover attaching area for nicks. Use a flat file to remove any nicks.
  13. Inspect the mating surfaces of the transmission case.
  14. Use the following procedure to measure the engine block flange runout at the mounting bolt hole bosses:
    1. Temporarily install the crankshaft. Measure the crankshaft flange runout.
    2. Hold a gauge plate flat against the crankshaft flange.
    3. Place J 8001  (dial indicator stem) on the transmission mounting bolt hole boss. Set the indicator to zero.
    4. Record the readings obtained from all of the bolt hole bosses. The measurements should not vary more than 0.25 mm (0.010 in).
    5. Recheck the crankshaft flange runout if the readings vary more than 0.25 mm (0.010 in). If the crankshaft flange runout is within the specification, replace the engine block.
    15. Fig 4: Checking Crankshaft Main Bearing Bores
    GM637758Courtesy of GENERAL MOTORS CORP.
  15. Remove the crankshaft.
    16. NOTE: Refer to Fastener Notice in Cautions and Notices.
  16. Re-install the crankshaft bearing caps, stiffener, and bolts.

    Tighten: 

    1. Tighten the crankshaft bearing cap bolts to 25 N.m (18 lb ft).
    2. Use J 45059  to tighten the crankshaft bearing cap bolts an additional 180 degrees. See Special Tools and Equipment .

    17. IMPORTANT: Perform the following inspections, and reconditioning (if necessary), with the crankshaft main bearing caps installed and tightened to specification.
  17. Inspect the crankshaft main bearing bores. Use J 8087  to measure the bearing bore concentricity and alignment. See Special Tools and Equipment .
  18. Remove the crankshaft main bearing cap stiffener and main bearing caps with bearings.
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