GrandPrix, Impala 2006-2008, Monte Carlo 2006-2007

Alternator

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Diagnosis & Testing



Load Test
  1. With the engine running, turn on the blower motor and the high beams ( or other electrical accessories to place a load on the charging system).
  2.  
  3. Increase and hold engine speed to 2000 rpm.
  4.  
  5. Measure the voltage reading at the battery.
  6.  
  7. The voltage should increase at least 0.5 volts from the voltage test. If the voltage does not meet specifications, the charging system is malfunctioning.
    NOTE
    Usually under and overcharging is caused by a defective alternator, or its related parts (regulator), and replacement will fix the problem; however, faulty wiring and other problems can cause the charging system to malfunction. Many automotive parts stores have alternator bench testers available for use by customers. An alternator bench test is the most definitive way to determine the condition of your alternator.

  8.  

No Load Test
  1. Connect a tachometer to the engine.
    CAUTION
    Ensure that the transmission is in Park and the emergency brake is set. Blocking a wheel is optional and an added safety measure.

  2.  
  3. Turn off all electrical loads (radio, blower motor, wipers, etc.)
  4.  
  5. Start the engine and increase engine speed to approximately 1500 rpm.
  6.  
  7. Measure the voltage reading at the battery with the engine holding a steady 1500 rpm. Voltage should have raised at least 0.5 volts, but no more than 2.5 volts.
  8.  
  9. If the voltage does not go up more than 0.5 volts, the alternator is not charging. If the voltage goes up more than 2.5 volts, the alternator is overcharging.
    NOTE
    Usually under and overcharging is caused by a defective alternator, or its related parts (regulator), and replacement will fix the problem; however, faulty wiring and other problems can cause the charging system to malfunction. Many automotive parts stores have alternator bench testers available for use by customers. An alternator bench test is the most definitive way to determine the condition of your alternator.

  10.  
  11. If the voltage is within specifications, proceed to the next test.
  12.  

Voltage Test
  1. Make sure the engine is OFF , and turn the headlights on for 15-20 seconds to remove any surface charge from the battery.
  2.  
  3. Using a DVOM set to volts DC, probe across the battery terminals.
  4.  
  5. Measure the battery voltage.
  6.  
  7. Write down the voltage reading and proceed to the next test.
  8.  

Removal & Installation



3.4L Engine
  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Remove or disconnect the following:

    Negative battery cable
     
    Engine compartment cross brace
     
    Accessory drive belt
     
    Coolant recovery reservoir and place it aside
     
    Alternator bolts
     
    Alternator electrical connector
     
    Alternator
     

  4.  

To install:

  1. Install or connect the following:

    Alternator
     
    Alternator output BAT wire and torque the nut to 15 ft. lbs. (20 Nm)
     
    Alternator electrical connector
     
    Alternator bolts and torque them to 37 ft. lbs. (50 Nm)
     
    Coolant recovery reservoir
     
    Drive belt
     
    Negative battery cable
     

  2.  

3.5L & 3.9L Engine
  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Drain the cooling system.
  4.  
  5. Remove or disconnect the following:

    Battery and tray
     
    Drive belt
     
    Engine cooling fan assembly
     
    Thermostat housing and radiator hose
     
    Outboard/inboard alternator bolts
     
    Idler pulley bolt and pulley
     
    Alternator electrical connectors
     
    Alternator bolts and the alternator

    Click image to see an enlarged view

    Fig. View of the alternator-3.5L engine

     

  6.  

To install:

  1. Install or connect the following:

    Alternator
     
    Alternator electrical connectors. Torque the positive battery terminal to 15 ft. lbs. (20 Nm).
     
    Idler pulley and torque the bolt to 37 ft. lbs. (50 Nm)
     
    Alternator bolts and torque them to 37 ft. lbs. (50 Nm)
     
    Thermostat housing with radiator hose and torque the bolts to 80 inch lbs. (9 Nm)
     
    Engine cooling fan assembly
     
    Drive belt
     
    Battery tray and torque the bolts to 44 inch lbs. (5 Nm)
     
    Battery
     

  2.  
  3. Refill the cooling system.
  4.  

3.8L Engines
  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Remove or disconnect the following:

    Negative battery cable
     
    Drive belt
     
    Alternator electrical connectors
     
    Rear alternator brace
     
    Alternator bolts and the alternator

    Click image to see an enlarged view

    Fig. Alternator mounting-3.8L engine

     

  4.  

To install:

  1. Install or connect the following:

    Alternator
     
    Alternator bolts and torque them to 37 ft. lbs. (50 Nm)
     
    Alternator electrical connectors and torque the positive battery terminal to 15 ft. lbs. (20 Nm)
     
    Rear alternator brace and torque the bolts to 37 ft. lbs. (50 Nm)
     
    Accessory drive belt
     
    Negative battery cable
     

  2.  

5.3L Engine
  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Disconnect the negative battery cable. .
  4.  
  5. Remove the engine sight shield.
  6.  
  7. Remove the drive belt.
  8.  
  9. Disconnect the generator electrical connector (2).
  10.  
  11. Position aside the protective boot (1) from the generator output BAT terminal for access.
  12.  
  13. Remove the generator output BAT terminal nut (4) and remove the positive battery lead (3) from the generator.
  14.  
  15. Remove the generator bolts and generator.

    Click image to see an enlarged view

    Fig. Alternator mounting-5.3L engine

  16.  

To install:

  1. Install the generator and bolts. Tighten the bolts to 37 ft. lbs. (50 Nm).
  2.  
  3. Install the positive battery lead (3) and generator output BAT terminal nut (4) to the generator. Tighten the nut to 15 ft. lbs. (20 Nm).
  4.  
  5. Position the protective boot (1) to the generator output BAT terminal.
  6.  
  7. Connect the generator electrical connector (2).
  8.  
  9. Install the drive belt.
  10.  
  11. Install the engine sight shield.
  12.  
  13. Connect the negative battery cable.
  14.  

 
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