Here's a general outline of the steps involved:
1. Preparation:
* Safety First: Disconnect the negative battery cable. This is crucial to prevent electrical shocks and short circuits. Some mechanics also disconnect the positive cable, but negative first is standard practice.
* Gather Tools: You'll likely need a socket wrench set (metric), ratcheting wrenches, a breaker bar (possibly), pliers, a screwdriver (possibly Phillips and flathead), and possibly a wrench to loosen the serpentine belt tensioner. A jack and jack stands are also highly recommended for easier access. Consider using gloves and safety glasses.
* Consult a Repair Manual: A Haynes or Chilton manual for your specific vehicle year and model will provide detailed diagrams, torque specifications, and step-by-step instructions. This is highly recommended.
2. Accessing the Alternator:
* Raise the Vehicle (Recommended): Use a jack and jack stands to safely lift the front of your vehicle. Ensure it's securely supported before proceeding.
* Remove the Serpentine Belt: This is often the most challenging part. You'll need to locate the serpentine belt tensioner pulley. This pulley is usually released by using a special tool or a long wrench to push or turn it, thus relieving the tension on the belt. Consult your repair manual for the exact location and method for your vehicle. Once tension is relieved, you can slip the belt off the alternator pulley.
* Remove Electrical Connections: Unplug the electrical connectors from the back of the alternator. Carefully note how they are connected for reassembly.
3. Removing the Alternator:
* Remove Bolts: The alternator is usually held in place by two or three bolts. These can be difficult to access, depending on your vehicle's configuration. You may need extensions and a universal joint for your socket wrench.
* Remove the Alternator: Once the bolts are removed, carefully remove the alternator. It may be heavy, so be prepared.
4. Installing the New Alternator:
* Install in Reverse Order: Install the new alternator in the reverse order of removal. Make sure the alternator is securely bolted in place. Refer to your repair manual for proper torque specifications.
* Reconnect Electrical Connections: Reattach the electrical connectors to the back of the new alternator, ensuring they are securely seated.
* Install the Serpentine Belt: Reinstall the serpentine belt, ensuring it's correctly routed over all the pulleys, including the alternator pulley. Release the tensioner pulley slowly to allow the belt to seat onto the pulleys.
5. Final Steps:
* Lower the Vehicle: Carefully lower the vehicle from the jack stands.
* Reconnect Battery Cable: Connect the negative battery cable.
* Test the Alternator: Start the engine and check the battery voltage using a multimeter. It should read around 13.5-14.5 volts. A lower reading could indicate a problem with the new alternator or the charging system.
Important Considerations:
* Belt Routing: Make absolutely sure the serpentine belt is routed correctly. Incorrect routing can lead to premature belt wear or damage to other components.
* Torque Specifications: Always tighten bolts to the manufacturer's specified torque. Over-tightening can damage components, while under-tightening can cause looseness and failure.
* Disposal of Old Alternator: Dispose of the old alternator properly according to your local regulations. It contains recyclable materials.
This is a general overview. Again, consult a repair manual specific to your 1999 Pontiac Grand Am 6-cylinder before attempting this repair. If you're not comfortable with automotive repair, it's best to take your vehicle to a qualified mechanic. Improper repairs can lead to significant damage and safety hazards.
