Cobalt 2006-2008, G5 2007

Alternator

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Diagnosis & Testing



The alternator provides power consuming components with current while the engine is running and maintains battery charge. The alternator is mounted on the front edge of the engine. The output of the alternator depends on engine speed. When the engine is idling, the alternator operates at approximately half of maximum output. When the engine is idling with many power consuming components engaged, the alternator may be unable to maintain full battery charge.

The alternator creates an alternating current which is converted to a direct current in the rectifier bridge. The alternator also utilizes a built-in voltage regulator.

  1. Check that the wiring is in good condition.
  2.  
  3. Check for any abnormal noise from the alternator while the engine is running.
  4.  
  5. Check the accessory drive belt for wear or slipping.
    NOTE
    With the engine running at 2,500 RPM, headlights on and fan blower on high, the alternator output voltage should be 12.0-15.5 volts at 68°F.

  6.  

Removal & Installation



2.0L Engine
  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Disconnect negative battery cable.
  4.  
  5. Remove the accessory drive belt.
  6.  
  7. Remove the supercharger.
  8.  
  9. Remove the oil level indicator tube bolt and reposition the tube slightly for clearance.
  10.  
  11. Disconnect the alternator connectors.
  12.  
  13. Remove the alternator bolts.
  14.  
  15. Remove the alternator from the vehicle.
  16.  

To install:

  1. Position the alternator on the engine.
  2.  
  3. Install the alternator bolts. Tighten the alternator bolts to 18 ft. lbs. (25 Nm).
  4.  
  5. Connect the positive battery harness to the alternator battery terminal. Tighten the alternator terminal nut to 15 ft. lbs. (20 Nm).
  6.  
  7. Connect the alternator harness connectors.
  8.  
  9. Position the oil level indicator tube into the correct installed position and install the retaining bolt. Tighten the bolt to 89 inch lbs. (10 Nm).
  10.  
  11. Install the supercharger.
  12.  
  13. Install the drive belt.
  14.  
  15. Connect the battery negative cable.

    Click image to see an enlarged view

    Fig. Alternator mounting-2.0L engine

  16.  

2.2L & 2.4L Engines
  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Disconnect negative battery cable.
  4.  
  5. Remove the accessory drive belt.
  6.  
  7. Remove the air cleaner outlet resonator.
  8.  
  9. Disconnect the alternator connectors.
  10.  
  11. Remove the alternator bolts.
  12.  
  13. Remove the alternator from the vehicle.
  14.  

To install:

  1. Position the alternator on the engine.
  2.  
  3. Install the alternator bolts. Tighten the alternator bolts to 16 ft. lbs. (22 Nm).
  4.  
  5. Connect the positive battery harness to the alternator battery terminal. Tighten the alternator terminal nut to 15 ft. lbs. (20 Nm).
  6.  
  7. Connect the alternator harness connectors.
  8.  
  9. Install the air cleaner outlet resonator.
  10.  
  11. Install the accessory drive belt.
  12.  
  13. Connect the battery negative cable.

    Click image to see an enlarged view

    Fig. Alternator mounting-2.2L engine

  14.  

 
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