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Home >> GMC >> 2021 >> Yukon XL AT4 >> Repair and Diagnosis >> Engine Mechanical >> Mechanical >> Engine Mechanical - 5.3L (L84) Or 6.2L (L87) - Repair Instructions ( 5 Of 12) >> Repair Instructions >> Valve Lifter Guide Replacement - Left Side (L84) >> Cleaning and Inspection Procedure - Conditional

Cleaning and Inspection Procedure - Conditional

NOTE:

Perform the following cleaning and inspection or overhaul steps, as necessary. ONLY perform steps when components are removed with the intention of reinstallation.

  1. GM4957Courtesy of GENERAL MOTORS COMPANY
    NOTE:
    • When cleaning a cylinder head in a thermal type oven, do not exceed 204°C (400°F).
    • Be careful not to scuff the chamber.

    Clean the following components:

    1. Use the J-8089  Carbon Removal Brush (1) in order to remove the carbon from the combustion chambers.
    2. Gasket surfaces
    3. Valve stems and heads on a buffing wheel
    4. Bolt hole threads
    5. Remove all dirt, debris, or threadlocking material from the bolt holes.
  2. GM5700744Courtesy of GENERAL MOTORS COMPANY

    Inspect the fuel rail injector bores and clean with EN-47909  Injector Bore and Sleeve Cleaning Kit (1), if required.

  3. Inspect the cylinder head for the following conditions:
    1. Cracks in the exhaust ports and combustion chambers
    2. External cracks in the water chambers
    3. Gasket surfaces for excessive scratches or gouging
    4. Bolt hole threads for debris or damaged threads
  4. GM5367575Courtesy of GENERAL MOTORS COMPANY

    Inspect the cylinder head for warpage. Engine Mechanical Specifications (L84)

  5. GM4960Courtesy of GENERAL MOTORS COMPANY

    Using the J-9666  Valve Spring Tester (1), measure the valve spring tension. Engine Mechanical Specifications (L84) .

  6. GM5541591Courtesy of GENERAL MOTORS COMPANY

    Clean all sealing surfaces.

  7. Dry the intake manifold with compressed air.
  8. Inspect the intake manifold cylinder head deck for warpage.
  9. Place a straight edge (1) across the intake manifold cylinder head deck surface.
  10. Inspect the intake manifold for the following conditions:
    1. Inspect for loose threaded inserts or studs.
    2. Inspect for damaged or broken vacuum fitting.
    3. Inspect the intake manifold assembly for cracks or other damage.
    4. Inspect for damaged intake manifold gasket sealing surfaces.
  11. Position the straight edge (1) across a minimum of two runner port openings and check for warpage using a feeler gage. Engine Mechanical Specifications (L84)
  12. Inspect the ventilation system passages for restrictions.
  13. GM5035044Courtesy of GENERAL MOTORS COMPANY

    Clean the exhaust manifold (1) and heat shield (2) in solvent.

  14. Dry the exhaust manifold (1) with compressed air.
  15. Inspect the exhaust manifold (1) to the cylinder head exhaust manifold gasket surface for excessive scratches or gouging.
  16. Inspect for a loose, damaged, or cracked heat shield (2).
  17. Inspect the heat shield bolts (3) for damaged threads.
  18. GM5035045Courtesy of GENERAL MOTORS COMPANY

    Use a straight edge (1) and a feeler gauge and measure the exhaust manifold cylinder head deck for warpage.

    An exhaust manifold cylinder head deck with warpage in excess of 0.25 mm (0.01 in) within the 2 front or 2 rear runners or 0.5 mm (0.02 in) overall, may cause an exhaust leak. Exhaust manifolds not within specifications MUST be replaced.

  19. GM5035067Courtesy of GENERAL MOTORS COMPANY

    Remove the ignition coil bolts (1) and ignition coils (2) before cleaning the valve rocker arm cover in solvent. Do not submerge the ignition coils in solvent.

  20. Inspect the valve rocker arm covers (3) for the following conditions:
    1. Scoring or damage to the gasket surfaces
    2. Ventilation system passages for restrictions
    3. Threaded bolt holes for damage or debris
  21. GM5035068Courtesy of GENERAL MOTORS COMPANY
    NOTE:

    Components that are to be used again must be marked, sorted or organized for assembly.

    Clean the components in cleaning solvent.

  22. Dry the components with compressed air.
  23. Inspect the valve lifters for the following conditions:
    1. Broken or collapsed spring (1)
    2. Worn pushrod socket (2)
    3. Plugged lubrication hole (3)
    4. Plugged lifter oil switching hole (4)
    5. Flat spots on the roller (5)
    6. Worn or damaged roller bearing (6)

      The roller should rotate freely with no binding or roughness.

    7. Scuffed or worn sides (7)
  24. GM5035070Courtesy of GENERAL MOTORS COMPANY

    Inspect the valve lifter guides for the following conditions:

  25. Cracks or damage (1)
  26. Excessive wear in the lifter mounting bores (2)
  27. GM5035065Courtesy of GENERAL MOTORS COMPANY
    NOTE:

    Parts that are to be used again must be marked, sorted or organized for assembly.

    Mark, sort, or organize the components for assembly.

  28. Clean the components with cleaning solvent.
  29. Dry the components with compressed air.
  30. Inspect the valve rocker arms bearings (2) for binding or roughness.
  31. Inspect the valve rocker arm pushrod sockets (3) and valve stem mating surfaces (1). These surfaces should be smooth with no scoring or exceptional wear.
  32. Inspect the pushrods for worn or scored ends. These surfaces should be smooth with no scoring or exceptional wear.
  33. Inspect the pushrods for bends. Roll the pushrod on a flat surface to determine if the pushrod is bent.
  34. Inspect the pushrod oil passages for restrictions.
  35. Inspect the rocker arm pivot supports for cracks, wear, or other damage.
  36. NOTE:

    Spark plug wire integrity is vital for proper engine operation. A thorough inspection will be necessary to accurately identify conditions that may affect engine operation.

  37. Inspection the spark plug wire for the following conditions:
    1. Correct routing of the spark plug wires. Incorrect routing may cause cross-firing.
    2. Inspect for any signs of cracks or splits in the wires.
  38. Inspect each boot for the following conditions:
    1. Tearing
    2. Piercing
    3. Arcing
    4. Carbon tracking
    5. Corroded terminals
  39. If corrosion, carbon tracking or arcing are indicated on a spark plug wire boot or on a terminal, replace the wire and the component connected to the wire.