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For 1990-2009 cars only

Exhaust Manifold Replacement - Right Side LS4

Removal Procedure


    Object Number: 1554543  Size: SH
  1. Remove the engine sight shield. Refer to Upper Intake Manifold Sight Shield Replacement.
  2. Remove the spark plugs. Refer to Spark Plug Replacement.
  3. Remove the exhaust crossover pipe nuts from the right exhaust manifold.
  4. Disconnect the catalytic converter from the exhaust manifold. Refer to Catalytic Converter Replacement.
  5. Support the catalytic convertor and exhaust system with the mechanics wire.
  6. Lower the vehicle.
  7. Remove the ignition coil. Refer to Ignition Coil Replacement.
  8. Remove the heated oxygen sensor (HO2S). Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 1.

  9. Object Number: 1411890  Size: SH
  10. Remove the exhaust manifold heat shield bolts (604).
  11. Remove the exhaust manifold heat shield (603).

  12. Object Number: 1411888  Size: SH
  13. Remove the exhaust manifold bolts.
  14. Remove the exhaust manifold.
  15. Remove and discard the exhaust manifold gasket.

Installation Procedure

Note: 

   • Tighten the exhaust manifold bolts as specified in the service procedure. Improperly installed and/or leaking exhaust manifold gaskets my affect vehicle emissions and/or On Board Diagnostic (OBD) II system performance.
   • The cylinder head exhaust manifold bolt hole threads must be clean and free of debris or threadlocking material.
   • DO NOT apply threadlock to the first three thread of the bolts.


    Object Number: 1411888  Size: SH
  1. Apply a 5 mm (0.2 in) wide band of threadlock GM P/N 12345493 (Canadian P/N 10953488) or equivalent to the threads of the exhaust manifold bolts.
  2. Caution: Refer to Fastener Caution in the Preface section.

  3. Install a NEW exhaust manifold gasket, the exhaust manifold and bolts.
  4. Tighten

        • Tighten the bolts a first pass to 15 N·m (11 lb ft). Tighten the bolts beginning with the center 2 bolts. Alternate from side to side, and work toward the outside.
        • Tighten the bolts a final pass to 20 N·m (15 lb ft). Tighten the bolts beginning with the center 2 bolts. Alternate from side to side, and work toward the outside.
  5. Using a flat punch, bend over the exposed edge of the exhaust manifold gasket at the rear of the right cylinder head.

  6. Object Number: 1411890  Size: SH
  7. Install the exhaust manifold heat shield (603).
  8. Install the exhaust manifold heat shield bolts (604).
  9. Tighten
    Tighten the bolts to 9 N·m (80 lb in).

  10. Install the O2 sensor. Refer to Spark Plug Replacement.
  11. Raise the vehicle.
  12. Remove the mechanics wire from the exhaust system and connect the catalytic converter. Refer to Catalytic Converter Replacement.

  13. Object Number: 1554543  Size: SH
  14. Install the exhaust crossover pipe nuts to the right exhaust manifold.
  15. Tighten
    Tighten the nuts to 25 N·m (18 lb ft).

  16. Install the ignition coil. Refer to Ignition Coil Replacement.
  17. Install the spark plugs. Refer to Spark Plug Replacement.
  18. Install the fuel injector sight shield. Refer to Upper Intake Manifold Sight Shield Replacement.

Exhaust Manifold Replacement - Right Side LZE/LZ4/LZ8

Special Tools

J 39194-B Heated Oxygen Sensor Socket

Removal Procedure


    Object Number: 1609170  Size: SH
  1. Remove the generator. Refer to Generator Replacement.
  2. Remove the connector position assurance (CPA) retainer (3).
  3. Disconnect the heated oxygen sensor (HO2S) electrical connector (2).
  4. Remove the HO2S clip (1) from the ignition coil bracket.

  5. Object Number: 1618175  Size: SH

    Note: The HO2S uses a permanently attached pigtail and connector. This pigtail should not be removed from the sensor. Damage or removal of the pigtail or connector will affect proper operation of the sensor.

  6. Remove the HO2S using the J 39194-B .

  7. Object Number: 1618181  Size: SH
  8. Remove the exhaust manifold shield bolts.
  9. Remove the exhaust manifold shield.

  10. Object Number: 1617973  Size: SH
  11. Remove the exhaust crossover pipe heat shield bolts.
  12. Remove the exhaust crossover pipe heat shield.

  13. Object Number: 1617975  Size: SH
  14. Remove the exhaust crossover pipe to right exhaust manifold nuts.

  15. Object Number: 1618188  Size: SH
  16. Remove the upper exhaust manifold bolts.
  17. Remove the catalytic converter. Refer to Catalytic Converter Replacement.
  18. Remove the lower exhaust manifold bolts.
  19. Remove the exhaust manifold.
  20. Remove and discard the exhaust manifold gasket.

Installation Procedure


    Object Number: 1618188  Size: SH
  1. Install a NEW exhaust manifold gasket onto the cylinder head studs.
  2. Install the exhaust manifold.
  3. Caution: Refer to Fastener Caution in the Preface section.

  4. Install the lower exhaust manifold bolts.
  5. Tighten
    Tighten the bolts to 20 N·m (15 lb ft).

  6. Install the catalytic converter. Refer to Catalytic Converter Replacement.
  7. Lower the vehicle.
  8. Install the upper exhaust manifold bolts.
  9. Tighten
    Tighten the bolts to 20 N·m (15 lb ft).


    Object Number: 1617975  Size: SH
  10. Install the exhaust crossover pipe to right exhaust manifold nuts.

  11. Object Number: 1617973  Size: SH
  12. Install the exhaust crossover pipe heat shield.
  13. Install the exhaust crossover pipe heat shield bolts.

  14. Object Number: 1618181  Size: SH
  15. Install the exhaust manifold shield.
  16. Install the exhaust manifold shield bolts.
  17. Tighten
    Tighten the bolts to 10 N·m (89 lb in).


    Object Number: 1618175  Size: SH

    Note: Whenever the oxygen sensor is removed, coat the threads with nickel-based anti-seize compound such as GM P/N 5613695 (or equivalent).

  18. Install the HO2S using J 39194-B .
  19. Tighten
    Tighten the sensor to 42 N·m (31 lb ft).


    Object Number: 1609170  Size: SH
  20. Connect the HO2S electrical connector (2).
  21. Install the CPA retainer (3).
  22. Install the HO2S clip (1) to the ignition coil bracket.
  23. Install the generator. Refer to Generator Replacement.