General Procedure (Consult your repair manual for specifics):
1. Safety First! Disconnect the negative battery terminal before starting any work on the vehicle's electrical system. This prevents accidental shorts or injury. Support the vehicle securely on jack stands. Never work under a vehicle supported only by a jack.
2. Locate the Tensioner: Identify the specific automatic tensioner on your Bonneville's engine. It's usually located near the serpentine belt.
3. Release Belt Tension: This is the critical step. The method varies:
* Bolt-type tensioner: Some tensioners have a bolt that, when loosened, allows the tensioner to retract, releasing the belt. Consult a repair manual to find the location of this bolt. Use the correct size wrench or socket to loosen it. You may need a wrench or socket with an extension to reach it.
* Lever-type tensioner: Others use a lever arm that needs to be pressed or pulled to release the tension. A specialized tool or even a sturdy pry bar (used carefully) might be required. Be very careful not to damage the tensioner.
4. Remove the Serpentine Belt: Once the tension is released, carefully remove the serpentine belt from the pulleys.
5. Pulley Removal: Now, you should be able to access the pulley on the tensioner. There are typically two ways the pulley is attached:
* Nut and bolt: The pulley is usually secured with a nut and bolt. Use the appropriate socket and wrench to remove the nut and bolt, then carefully pull the pulley off the shaft.
* Press-fit: In some cases, the pulley is press-fitted onto the shaft. This requires a pulley puller tool. This tool grabs the pulley and pulls it off the shaft without damaging it. Improvising can damage the tensioner.
6. Inspection and Replacement (If Necessary): Inspect the pulley for wear, cracks, or damage. If damaged, replace it with a new one.
7. Reassembly: Reverse the process carefully to reinstall the pulley, serpentine belt, and tighten everything to the manufacturer's specifications (found in your repair manual).
Crucial Safety Considerations:
* Consult a Repair Manual: A factory service manual specific to your 1998 Pontiac Bonneville is essential. It will show you exactly where the tensioner is, how to release the tension, and the correct torque specifications for tightening bolts. Improper torque can damage the tensioner or other components.
* Proper Tools: Use the correct size and type of tools. Improper tools can cause damage or injury.
* Caution with Springs: Automatic tensioners contain strong springs. Be prepared for the sudden release of tension when releasing the belt.
* Sharp Edges: Be mindful of sharp edges on pulleys and other engine components.
* Professional Help: If you are not comfortable performing this task yourself, it's always best to take your vehicle to a qualified mechanic.
Remember, working on a vehicle's engine involves inherent risks. If you're unsure about any step, seek professional assistance to avoid damaging your car or injuring yourself.
