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Home >> Chevrolet >> 2023 >> Tahoe SSV >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 19 (Engine Mechanical - 3.0L (Lm2) Diesel - Repair Instructions (11 Of 11)) >> Repair Instructions >> Engine Block Overhaul >> Cleaning and Inspection Procedure - Required

Cleaning and Inspection Procedure - Required

WARNING: This page is about a different variant/trim than selected.
  1. GM5044132Courtesy of GENERAL MOTORS COMPANY

    Clean the automatic transmission flex plate (3) in solvent.

  2. Dry the flex plate (3) with compressed air.
  3. Inspect the flex plate (3) for the following conditions:
    1. Stress cracks around the flex plate to torque converter mounting bolt hole locations (1) and flex plate to crankshaft (2, 4)
    2. NOTE:

      Do not attempt to repair the welded areas that retain the ring gear to the flex plate. Install a NEW flex plate.

    3. Cracks at welded areas that retain the ring gear onto the flex plate (3)
    4. Damaged or missing ring gear teeth (5)
  4. GM5863033Courtesy of GENERAL MOTORS COMPANY

    Clean the camshaft sprocket (1) surfaces.

  5. Inspect the camshaft sprocket (1) for grooves, excessive wear, chipping, or embedded bearing material.
  6. Replace the camshaft sprocket (1) if damaged.
  7. GM5148844Courtesy of GENERAL MOTORS COMPANY

    Clean the connecting rods (1) in solvent and dry with compressed air.

  8. Inspect the connecting rod (1) for the following:
    1. Signs of being twisted, bent, nicked or cracked
    2. Scratches or abrasion on the connecting rod (1) bearing seating surfaces
  9. If the connecting rod bores (2) contain minor scratches or abrasions, clean the bores in a circular direction with a light emery paper. DO NOT scrape the connecting rod (1) or connecting rod cap.
  10. If the beam of the connecting rod (1) is scratched or has other damage replace the connecting rod.
  11. GM5148845Courtesy of GENERAL MOTORS COMPANY

    Clean the piston with a cleaning solvent. Do NOT wire brush any parts of the piston.

  12. Clean the piston ring grooves.
  13. Inspect the piston on the following:
    1. Cracked ring lands, skirts or pin bosses
    2. Ring grooves for nicks
    3. Eroded areas on the top of the piston (1)
    4. Scored or damaged skirts (2)
    5. Worn piston pin bores (3)
  14. If there is any excessive wear, replace the piston.
  15. GM5845653Courtesy of GENERAL MOTORS COMPANY

    Measure the clearance between the piston pin (1) and the piston bore. Use the following procedure:

    1. Measure the piston pin outside diameter (a).
    2. Measure the piston bore diameter (b).
    3. Substract the piston pin outside diameter (a) from the piston bore diameter (b) to calculate the clearance.
    4. For the correct value of the clearance piston pin (1) in the piston (2). Engine Mechanical Specifications
  16. GM5845654Courtesy of GENERAL MOTORS COMPANY

    Inspect the connecting rod piston pin bore for any signs of pitting or erosion. If any pitting or erosion is present replace the connecting rod.

  17. Measure the clearance between the piston pin (1) and the connecting rod bore. Use the following procedure:
    1. Measure the piston pin outside diameter (a).
    2. Measure the connecting rod bore diameter (b).
    3. Substract the piston pin outside diameter (a) from the connecting rod diameter (b) to calculate the clearance.
    4. For the correct value of the clearance piston pin (1) in the connecting rod (2). Engine Mechanical Specifications
  18. If there is excessive clearance, replace the piston pin (1) and repeat the measurements.
  19. If there is still excessive clearance, replace the connecting rod (2).
  20. If there is excessive clearance, replace the piston pin (1) and repeat the measurements.
  21. If there is still excessive clearance, replace the piston.
  22. GM5148848Courtesy of GENERAL MOTORS COMPANY

    Install each piston ring to the cylinder (1) and measure the piston ring end gap at the points mentioned in the step below.

  23. GM5227919Courtesy of GENERAL MOTORS COMPANY

    Measure piston ring end gap at point a:

    1. The piston compression upper ring end gap. Place the piston ring in the area of the bore where the piston ring will travel, approximately 10 mm (0.394 in) down from the deck surface. Engine Mechanical Specifications
    2. The piston compression lower ring end gap. Place the piston ring in the area of the bore where the piston ring will travel, approximately 10 mm (0.394 in) down from the deck surface. Engine Mechanical Specifications
    3. The piston oil ring rail end gap. Place the piston ring in the area of the bore where the piston ring will travel, approximately 10 mm (0.394 in) down from the deck surface. Engine Mechanical Specifications
  24. Measure piston ring end gap at point b:
    1. The piston compression upper ring end gap. Place the piston ring in the area of the bore where the piston ring will travel, approximately 42 mm (1.654 in) down from the deck surface. Engine Mechanical Specifications
    2. The piston compression lower ring end gap. Place the piston ring in the area of the bore where the piston ring will travel, approximately 42 mm (1.654 in) down from the deck surface. Engine Mechanical Specifications
    3. The piston oil ring rail end gap. Place the piston ring in the area of the bore where the piston ring will travel, approximately 42 mm (1.654 in) down from the deck surface. Engine Mechanical Specifications
  25. Measure piston ring end gap at point c:
    1. The piston compression upper ring end gap. Place the piston ring in the area of the bore where the piston ring will travel, approximately 140 mm (5.512 in) down from the deck surface. Engine Mechanical Specifications
    2. The piston compression lower ring end gap. Place the piston ring in the area of the bore where the piston ring will travel, approximately 140 mm (5.512 in) down from the deck surface. Engine Mechanical Specifications
    3. The piston oil ring rail end gap. Place the piston ring in the area of the bore where the piston ring will travel, approximately 140 mm (5.512 in) down from the deck surface. Engine Mechanical Specifications
  26. If the clearance is greater than the provided specifications, the piston rings must be replaced.
  27. GM5148849Courtesy of GENERAL MOTORS COMPANY

    Measure the piston ring axial clearance (1). Compare the measurements with those provided below:

    1. The piston compression upper ring clearance. For the correct value of the clearance. Engine Mechanical Specifications
    2. The piston compression lower ring clearance. For the correct value of the clearance. Engine Mechanical Specifications
    3. The piston oil ring rail clearance. For the correct value of the clearance. Engine Mechanical Specifications
  28. If the clearance is greater than the provided specifications, replace the piston rings and repeat the measurements.
  29. If the clearance is still greater than the provided specifications, replace the pistons.
  30. Measure the engine cylinder bore. Engine Block Overhaul 
  31. GM3966341Courtesy of GENERAL MOTORS COMPANY

    Using a micrometer (2) or caliper at a right angle to the piston, measure the width of the piston (1) at 3 different measuring points from the bottom of the skirt.

    1. First measure point 13 mm (0.512 in) from the bottom of the skirt.
    2. Second measure point 38 mm (1.496 in) from the bottom of the skirt.
    3. Third measure point 68.2 mm (2.685 in) from the bottom of the skirt.
  32. Subtract the piston (1) diameter from the cylinder bore diameter in order to calculate the piston-to-bore clearance.
  33. For the correct value of the clearance piston to bore. Engine Mechanical Specifications
  34. If the clearance obtained through measurement is greater than these specifications and the cylinder bores are within the specification, replace the piston (1).
  35. Install the connecting rod bearings and the connecting rod bearing caps.
  36. CAUTION:

    Refer to Fastener Caution .

  37. Connecting Rod Bolt - Install and tighten - Fastener Specifications
  38. GM2189741Courtesy of GENERAL MOTORS COMPANY

    Using an internal measuring device, measure the connecting rod bearing diameters at 3 different measuring points (1).

  39. Calculate the average connecting rod inner diameter.

    Formula: (1. result + 2. result + 3. result) / 3

  40. GM2189634Courtesy of GENERAL MOTORS COMPANY

    Using a micrometer gauge, measure the connecting rod journal diameter at 2 different measuring points between (1) and (3) and between (2) and (4).

  41. Calculate the average connecting rod journal diameter.

    Formula: (1. result + 2. result) / 2.

  42. Subtract the average connecting rod journal diameter from the average connecting rod bearing diameter in order to determine the connecting rod bearing clearance.
  43. For the correct value of the connecting rod bearing clearance. Engine Mechanical Specifications
  44. GM5845375Courtesy of GENERAL MOTORS COMPANY

    Clean the crankshaft (1) with solvent.

  45. Thoroughly clean all oil passages and inspect for restrictions or burrs.
  46. Dry the crankshaft (1) with compressed air.
  47. Inspect the 7 crankshaft bearing journals (2) and 6 connecting rod bearing journals (3) for wear:
    1. Grooves or scoring
    2. Scratches
    3. Pitting or embedded bearing material
  48. Inspect for grooves, scoring, scratches, pitting, or embedded bearing material in the following components:
    1. Oil pump drive belt sprocket teeth
    2. Crankshaft sensor sprocket teeth
    3. Timing chain sprocket teeth
  49. Damaged or missing crankshaft gear teeth (4)
  50. GM52051Courtesy of GENERAL MOTORS COMPANY

    Inspect crankshaft bearings (1) for craters or pockets. Flattened sections on the bearing halves also indicate fatigue.

  51. GM52053Courtesy of GENERAL MOTORS COMPANY

    Inspect the crankshaft bearings (1) for excessive scoring or discoloration.

  52. Inspect the crankshaft bearings (1) for dirt or debris embedded into the bearing material.
  53. GM52056Courtesy of GENERAL MOTORS COMPANY

    Inspect the crankshaft bearings (1) for improper seating indicated by bright, polished sections of the bearing.

  54. GM4980Courtesy of GENERAL MOTORS COMPANY
    NOTE:
    • The crankshaft main bearings are a precision insert type. Main bearing caps are machined with the engine block, for proper clearance, and cannot be shimmed or filed for bearing fit. If the clearances are found to be excessive, new bearings and/or engine block and cap repair or replacement may be required.
    • Do not rotate the crankshaft while gaging plastic is between the crankshaft journal and the bearing surface.
    • The crankshaft bearing clearances are critical. Excessive bearing clearance may affect crankshaft position sensor signals and may affect diagnostics and system operation.
    • Remove the bearing cap side bolts prior to cap removal.

    Remove the bearing caps, bearing half, and bolts.

  55. Install gaging plastic (1) onto the crankshaft journal. Install the gaging plastic the full width of the crankshaft bearing journal.
  56. Install and tighten the bearing caps, bearing half, and bolts. Engine Mechanical Specifications
  57. Remove the bearing caps, bearing half, and bolts.
  58. GM4981Courtesy of GENERAL MOTORS COMPANY

    Using the scale supplied with the plastic gaging kit, measure the gaging plastic (1) at its widest area.

    1. If the gaging plastic (1) shows irregularity in the journal, exceeding 0.025 mm (0.001 in), remove the crankshaft and measure the journal with a micrometer.
    2. If clearance cannot be brought to specifications, replace the crankshaft or engine block as required. Engine Mechanical Specifications
  59. NOTE:

    Different classes of bearing can be used for a crankshaft bearing to reduce bearing clearance. The stronger of the two bearing must be inserted in the crankshaft bearing cap.

  60. Crankshaft bearing clearance is calculated by using:
    1. Crankshaft bearing bore diameter
    2. Crankshaft bearing journal diameter
    3. Crankshaft bearing thickness
  61. Measure the crankshaft bearing play:
    1. Compare the width of the flattened plastic thread to the measuring scale.
    2. For the permissible crankshaft bearing clearance. Engine Mechanical Specifications
  62. GM5845387Courtesy of GENERAL MOTORS COMPANY

    Clean the crankshaft pulley (1).

  63. Inspect the crankshaft pulley (1) for damage to belt drive surface and to crankshaft pulley hub.
  64. Inspect the crankshaft pulley (1) hub groove for damage or wear.
  65. Replace the crankshaft pulley (1) if any damage is found.
  66. GM5148564Courtesy of GENERAL MOTORS COMPANY

    Remove any old sealant or gasket material from the cylinder head.

  67. Clean all cylinder head surfaces with non-corrosive cleaning solvent.
  68. Blow out all the oil galleries using compressed air.
  69. Remove any carbon deposits from the combustion chamber (2).
  70. Inspect the cylinder head sealing surface for flatness using a straightedge (1). If the cylinder head sealing surface is uneven, replace the cylinder head. Do NOT machine the cylinder head.
  71. Inspect all the threaded holes for damage. Threads may be reconditioned with thread inserts.
  72. Inspect the cylinder head camshaft bearing surfaces for the following conditions:
    1. Excessive scoring or pitting.
    2. Discoloration from overheating.
    3. Deformation from excessive wear.
  73. If any of the above conditions exist on the camshaft bearing surfaces, replace the cylinder head.
  74. GM5845370Courtesy of GENERAL MOTORS COMPANY

    Inspect the cylinder head (1) for the following:

    1. Cracks, damage, or pitting in the combustion chambers.
    2. Debris in the oil galleries, continue to clean the galleries until all debris is removed.
    3. Coolant leaks or damage to the deck face sealing surface, if coolant leaks are present, measure the surface warpage as described under cylinder head measurement deck flatness inspection.
    4. Damage to any gasket surfaces.
    5. Burnt or eroded areas in the combustion chamber.
    6. Cracks in the exhaust ports (3) and combustion chambers.
    7. External cracks in the water passages.
    8. Restrictions in the intake or exhaust ports (3).
    9. Restrictions in the cooling system passages.
    10. Rusted, damaged or leaking core plugs.
  75. Inspect the exterior of the camshaft housing ladder frame (2) for the following conditions:
    1. Damage to the camshaft housing ladder frame (4) bolt holes.
    2. Damage to the injector bore holes.
    3. Damage to the oil passages.
  76. Inspect the interior of the camshaft housing ladder frame (2) for the following conditions:
    1. Inspect the camshaft housing ladder frame (2), casting imperfections, cracks or damage.
    2. Inspect the camshaft housing ladder frame (2) seal locations (1) for cracks or damage.
  77. If the cylinder head (1) or ladder frame (2) is cracked or damaged, they must be replaced. No welding or patching of the is allowed.
  78. GM5863034Courtesy of GENERAL MOTORS COMPANY

    Clean the fuel injection pump driven sprocket (1) surfaces.

  79. Inspect the fuel injection pump driven sprocket (1) for grooves, excessive wear, chipping, or embedded bearing material.
  80. Replace the fuel injection pump driven sprocket (1) if damaged.
  81. GM5145895Courtesy of GENERAL MOTORS COMPANY
    NOTE:

    DO NOT soak or submerge the fuel rail or injectors in solvent.

    Clean the exterior of the high pressure diesel fuel injection rail (4) and high pressure diesel fuel injectors in solvent.

  82. Inspect the high pressure diesel fuel injection rail (4) and components for the following conditions:
    1. Damage, debris, or restrictions to the high pressure diesel fuel injection rail (4)
    2. Damage, debris, or restrictions to the fuel ports (2) at the high pressure diesel fuel injection rail (4)
    3. Damage to the mounting area or threads on the high pressure diesel fuel injection rail (4)
    4. Damage to the holes of the high pressure diesel fuel sensor (1) and fuel pressure regulator (3)
  83. GM6053740Courtesy of GENERAL MOTORS COMPANY

    Clean the high pressure diesel fuel pump (1) mating surfaces.

  84. Inspect the high pressure diesel fuel pump (1) for damage.
  85. Replace fuel injection pump (1) if any damage is found.
  86. Inspect the high pressure diesel fuel pump shaft notch (2) for damage.
  87. GM6053739Courtesy of GENERAL MOTORS COMPANY

    Inspect the keyway (1) on the sprocket for damage.

  88. GM5140935Courtesy of GENERAL MOTORS COMPANY

    Clean the valve rocker arms (1) and hydraulic valve lash adjusters (2) with solvent.

  89. Inspect the valve rocker arms (1).
  90. Inspect the hydraulic valve lash adjusters (2).
  91. GM5863028Courtesy of GENERAL MOTORS COMPANY

    Clean the oil pump sprocket (1) surfaces.

  92. Inspect the oil pump sprocket (1) for grooves, scoring, scratches, pitting, or embedded bearing material.
  93. Replace the oil pump sprocket (1) if damaged.
  94. GM5863031Courtesy of GENERAL MOTORS COMPANY

    Inspect the timing belt (1) for grooves, pitting, fraying, or missing teeth.

  95. Replace the timing belt (1) if damaged.
  96. GM5863012Courtesy of GENERAL MOTORS COMPANY

    Clean the primary timing chain (1) surfaces.

  97. Inspect the timing chain (1) for signs of excessive wear, chipping, or seizure of the timing chain links.
  98. Replace the timing chain (1) if damaged.
  99. GM5863015Courtesy of GENERAL MOTORS COMPANY

    Clean the primary timing chain guide (1) surfaces.

  100. Inspect the timing chain guide (1) for signs of cracking or wear.
  101. Replace the timing chain guides if wear exceeds 1.12 mm (0.045 in) of depth on the chain guide surface.
  102. GM5863014Courtesy of GENERAL MOTORS COMPANY

    Clean the secondary timing chain (1) surfaces.

  103. Inspect the timing chain (1) for signs of excessive wear, chipping, or seizure of the timing chain links.
  104. Replace the timing chain (1) if damaged.
  105. GM5863016Courtesy of GENERAL MOTORS COMPANY

    Clean the secondary timing chain guide (1) surfaces.

  106. Inspect the timing chain guide (1) for signs of cracking or wear.
  107. Replace the timing chain guides if wear exceeds 1.12 mm (0.045 in) of depth on the chain guide surface.
  108. GM5845392Courtesy of GENERAL MOTORS COMPANY

    Clean the timing chain lower cover (1).

  109. Clean the timing chain lower cover mating surfaces.
  110. Inspect the timing chain lower cover mating surfaces for damage.
  111. Inspect the crankshaft rear oil seal bore for damage.
  112. Inspect the fuel pump access hole cover (2) for damage.
  113. Replace the timing chain lower cover (1) if damaged.
  114. GM5863025Courtesy of GENERAL MOTORS COMPANY

    Clean the primary timing chain tensioner (1) surfaces.

  115. Inspect the timing chain tensioner (1) for wear.
  116. Replace the timing chain tensioner (1) if damaged.
  117. GM5863026Courtesy of GENERAL MOTORS COMPANY

    Clean the secondary timing chain tensioner (1) surfaces.

  118. Inspect the timing chain tensioner (1) for wear.
  119. Replace the timing chain tensioner (1) if damaged.
  120. GM6139308Courtesy of GENERAL MOTORS COMPANY
    CAUTION:

    The glow plug bore MUST be cleaned prior to glow plug installation. If the glow plug bore is not cleaned of carbon buildup prior to glow plug installation, it may cause severe damage to the glow plug. If the glow plug is damaged, the glow plug bore and combustion chamber must be cleaned of all debris, and the glow plug must be replaced.

    Using the EN-52074  Glow Plug Bore Reamer (1), clean the glow plug bore. Hole must be free of lubricant and grease.