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Home >> Chevrolet >> 2014 >> Malibu LS >> Repair and Diagnosis >> Engine Mechanical >> Mechanical >> Engine Mechanical - 2.0L (LTG) Or 2.5L (LKW) - Repair Instructions - Off Vehicle >> Repair Instructions - Off Vehicle >> Cylinder Head Cleaning and Inspection (LKW) >> Cylinder Head and Gasket Surface Cleaning and Inspection

Cylinder Head and Gasket Surface Cleaning and Inspection

    Fig 1: Spark Plugs
    GM2742595Courtesy of GENERAL MOTORS COMPANY
  1. Inspect the cylinder head locating pins. Remove the locating pins and discard, if necessary.
  2. Clean all of the gasket mating surfaces. Use the following procedures when cleaning the cylinder head and cylinder block surfaces:
    • Use a razor blade gasket scraper to clean the cylinder head and cylinder block gasket surfaces. Do not scratch or gouge any surface.
      • NOTE:

      Do not use any other method or technique to clean these gasket surfaces.

    • Use a new razor blade for each cylinder head and cylinder block.
      • NOTE:

      Be careful not to gouge or scratch the gasket surfaces. Do not gouge or scrape the combustion chamber surfaces. The feel of the gasket surface is important, not the appearance. There will be indentations from the gasket left in the cylinder head after all of the gasket material is removed. These small indentations will be filled in by the new gasket.

    • Hold the razor blade as parallel to the gasket surface as possible.
  3. Remove the spark plugs (1) using EN-39358  socket.
  4. Inspect the cylinder head gasket and mating surfaces for leaks, corrosion and blow-by. If the gasket has failed, use the following faults to determine the cause:
    1. Improper installation
    2. Loose or warped cylinder head
    3. Missing, off location or not fully seated dowel pins
    4. Corrosion in the seal area around the coolant passages
    5. Chips or debris in the cylinder head bolt holes
    6. Bolt holes in the cylinder block not drilled or tapped deep enough
    5. Fig 2: Locating Combustion Chambers
    GM415011Courtesy of GENERAL MOTORS COMPANY
  5. Inspect the cylinder head gasket surface.
    • Cylinder head may be reused if corrosion is found only outside a 4 mm (0.375 in) band around each combustion chamber (1).
    • Replace the cylinder head if the area between the valve seats is cracked (2).
    • Replace the cylinder head if corrosion has been found inside a 4 mm (0.375 in) band around each combustion chamber (3).
    6. NOTE:

    Do not use a wire brush on any gasket sealing surface.

  6. Remove the sealant from the rear cap mating surface with EN-28410  remover. Care must be used to avoid gouging or scraping the sealing surfaces.
  7. Clean the cylinder head. Remove all varnish, soot and carbon to the bare metal.
  8. Clean the valve guides.
    9. WARNING:

    Wear safety glasses to avoid injury when using compressed air or any cleaning solvent. Bodily injury may occur if fumes are inhaled or if skin is exposed to chemicals.

  9. Clean the threaded holes using the following procedure:
    1. First, use a nylon bristle brush.
    2. Use a suitable commercial spray liquid solvent and compressed air from an extended-tip blow gun to reach the bottom of the holes.
    3. Remove any broken long cylinder head bolts using the EN-38188  kit.
  10. Clean the remains of the sealer from the plug holes.
  11. Inspect the cylinder head for cracks. Check between the valve seats and in the exhaust ports.
    12. NOTE:

    Do not attempt to weld the cylinder head, replace it.

  12. Inspect the cylinder head deck for corrosion, sand inclusions and blow holes.
    13. Fig 3: Checking Cylinder Head Deck Surface For Flatness
    GM2146352Courtesy of GENERAL MOTORS COMPANY
  13. Using a straight edge (1) and feeler gauge (2), inspect the cylinder head deck surface for flatness. Refer to Engine Mechanical Specifications (LAF, LEA, or LUK) . If the cylinder head is out of specification, replace the cylinder head. Do not machine the cylinder head.
  14. Inspect all the threaded holes for damage. Threads may be reconditioned with thread inserts.
  15. Inspect the sealing surfaces.
    16. Fig 4: Cylinder Head Plugs
    GM2919837Courtesy of GENERAL MOTORS COMPANY
  16. Inspect the cylinder head plugs (1, 2) and verify the oil orifice is clear and free of debris.
    17. Fig 5: Camshaft Bearing Caps
    GM2919838Courtesy of GENERAL MOTORS COMPANY
  17. Inspect the camshaft bearing caps (3, 4, 5, 6) for damage.
  18. Inspect the camshaft front bearing cap (2) for damage.
  19. Inspect the camshaft lower bearing cap (7) for damage.
  20. Inspect the front bearing cap locating pins (1) for damage.
    21. Fig 6: Spark Plugs
    GM2742595Courtesy of GENERAL MOTORS COMPANY
    CAUTION:

    Refer to Component Fastener Tightening Caution .

  21. Install the spark plugs (1) using EN-39358  socket. Tighten the plugs to 20 N.m (15 lb ft).
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