Friday, October 14, 2011

How to replace Exhaust Manifold on 2006 Chevrolet Cobalt?


Exhaust Manifold



Removal & Installation



2.0L Engine
  1. Before servicing the vehicle, refer to the Precautions Section.
  2. Remove the exhaust manifold heat shield.
    WARNING
    The oxygen sensor uses a permanently attached pigtail and connector. Do not remove the pigtail from the oxygen sensor. Damage to or removal of the pigtail connector could affect proper operation of the oxygen sensor.


    WARNING
    The use of excessive force may damage the threads in the exhaust manifold/pipe.


    NOTE
    The in-line connector and louvered end must be kept clear of grease, dirt or other contaminants. Avoid using cleaning solvents of any type. DO NOT drop or roughly handle the oxygen sensor.


    NOTE
    The oxygen sensor may be difficult to remove when the engine temperature is less than 120°F (48°C).
  3. Remove the oxygen sensor.
    WARNING
    Do not bend the exhaust flex decoupler more than 3° in any direction. Movement of more than 3° will damage the exhaust flex decoupler.
  4. Disconnect the exhaust pipe from the manifold.

    Click image to see an enlarged view
    Fig. Exhaust manifold-2.0L engine; 2.2L similar
  5. Remove and discard the exhaust manifold to cylinder head retaining nuts.
  6. Remove the exhaust manifold.
  7. Clean all of the sealing surfaces.
To install:
  1. Install new exhaust manifold studs. Tighten the studs to 89 inch lbs. (10 Nm).
  2. Install the exhaust manifold gasket.
  3. Install the exhaust manifold to the cylinder head.
  4. Install NEW exhaust manifold to cylinder head retaining nuts finger tight.

    Click image to see an enlarged view
    Fig. Exhaust manifold torque sequence-2.0L engine
  5. Tighten the NEW exhaust manifold to cylinder head retaining nuts in sequence. Tighten the nuts to 124 inch lbs. (14 Nm).
  6. Connect the exhaust pipe. Tighten the nuts to 37 ft. lbs. (50 Nm).
  7. Coat the threads of the oxygen sensor with anti-seize compound.
    NOTE
    A special anti-seize compound is used on the oxygen sensor threads. The compound consists of a liquid graphite and glass beads. The graphite will burn away, but the glass beads will remain, making the sensor easier to remove. New or service sensors will have the compound applied to the threads. If a sensor is removed and is to be reinstalled, the threads must have an anti-seize compound applied before installation.
  8. Coat the threads of the oxygen sensor with anti-seize compound Saturn P/N 21485279, if necessary.
  9. Install the oxygen sensor. Tighten the oxygen sensor to 22 ft. lbs. (30 Nm).
  10. Install the exhaust manifold heat shield.
  11. Install the exhaust manifold heat shield bolts. Tighten the bolts to 17 ft. lbs. (23 Nm).

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