1. Identify the Belt(s): The Fiero likely has one or two belts depending on the engine (2.5L Iron Duke or 2.8L V6). Identify which belt needs adjusting. The serpentine belt drives the alternator, power steering pump, and water pump. Some models might have a separate belt for the AC compressor.
2. Loosen the Alternator Mounting Bolts: Locate the bolts securing the alternator to the engine block. There are typically two, and you'll need a wrench or socket to loosen them. Don't remove them completely, just loosen them enough to allow the alternator to move.
3. Adjust the Alternator Position: Once the bolts are loose, carefully push the alternator *towards the engine*. This will tighten the belt. You'll feel some resistance. The goal is to achieve the correct belt tension.
4. Check Belt Tension: The correct tension is crucial. There are several ways to check:
* Thumb Pressure: Press firmly on the longest span of the belt midway between the pulleys. It should deflect roughly 3/8 of an inch (about 1 centimeter). This is a commonly used method, but it's subjective.
* Twist Test (Less Recommended): Try twisting the belt 90 degrees. If it twists easily, it's too loose. If it's very difficult to twist, it's too tight. This method is less precise and can damage the belt.
5. Tighten the Alternator Bolts: Once you achieve the correct tension, securely tighten the alternator mounting bolts.
6. Recheck Tension: After tightening the bolts, double-check the belt tension again to ensure it hasn't loosened.
Important Considerations:
* Safety First: Disconnect the negative battery terminal before working on the belt to prevent accidental shorts.
* Proper Tools: Use the correct size wrenches or sockets to avoid stripping the bolts.
* Belt Condition: Inspect the belt for cracks, fraying, or excessive wear. If the belt is damaged, replace it. A worn belt can lead to serious engine problems.
* Consult a Repair Manual: A factory service manual for your specific 1987 Pontiac Fiero is highly recommended. It will provide detailed diagrams and instructions specific to your car's model and engine. Online resources may also offer diagrams and guidance.
If you're uncomfortable performing this task yourself, it's best to take your Fiero to a qualified mechanic. Improper belt tension can damage the belt, alternator, or other components.
