1. Safety First:
* Disconnect the negative battery cable. This is crucial to prevent electrical shocks and short circuits.
* Wear safety glasses. To protect your eyes from debris.
* Work in a well-ventilated area. If using a battery charger or jump starter.
2. Gather Your Tools:
* Socket wrench set (metric)
* Ratchet
* Extension(s)
* Wrenches (metric) – may need both open-end and box-end
* Pry bar (plastic or wood preferred to avoid scratching)
* New alternator (make sure you get the correct one for your specific engine)
* Battery charger (optional, but recommended to ensure a good charge after)
3. Accessing the Alternator:
The exact location and accessibility of the alternator will vary slightly depending on the engine (4.3L V6 or 2.8L V6). Generally, it's located at the front of the engine, towards the passenger side.
* Remove the serpentine belt: This is usually done using a serpentine belt tensioner tool. Consult your repair manual for the exact location and procedure. Some models may require you to loosen a bolt on the tensioner to release tension on the belt. Be careful, the belt can snap back with force.
* Locate the alternator mounting bolts. There are typically two or three bolts securing the alternator to the engine block or bracket.
4. Removing the Alternator:
* Disconnect the electrical connections: There will be two main connections: the large power cable and a smaller wire (usually for the alternator light in the dash). Use a wrench to loosen these nuts. Take note of where each wire goes for easy re-connection. A picture will be helpful.
* Remove the mounting bolts: Carefully remove the bolts holding the alternator in place.
* Remove the alternator: Once the bolts are removed, the alternator should be free. You may need to gently pry it loose from its position. Be mindful of any surrounding components.
5. Installing the New Alternator:
* Install the alternator: Carefully position the new alternator in place, aligning the mounting holes.
* Reconnect the mounting bolts: Tighten the bolts securely but do not over-tighten. Consult your repair manual for torque specifications.
* Reconnect the electrical connections: Attach the large power cable and the smaller wire, ensuring they are securely connected.
* Install the serpentine belt: Route the belt correctly around all the pulleys. Make sure it's seated correctly on each pulley.
6. Testing and Cleanup:
* Reconnect the negative battery cable.
* Start the engine: Check for any noises or issues. The alternator should be charging the battery (you can check this with a voltmeter). The battery charge indicator light on the dashboard should go out once the engine is running.
* Check the belt tension. Ensure it's properly tensioned and won't slip.
Important Considerations:
* Engine type: The exact location and access to the alternator will differ based on your specific engine. A 4.3L V6 will likely have different access than a 2.8L V6.
* Repair manual: A factory service manual for your specific year and model is invaluable. It will provide detailed instructions, torque specifications, and diagrams.
* Professional help: If you're uncomfortable performing this repair, it's best to seek professional help from a qualified mechanic.
This is a general overview, and the specific steps may vary. Always refer to a repair manual specific to your 1991 Chevy Blazer S-10 before beginning this repair. Improper installation can lead to damage or injury.
