1. Safety First:
* Park on a level surface: Engage the parking brake firmly.
* Disconnect the negative battery terminal: This prevents accidental shorts.
* Gather your tools: You'll need a socket wrench set (possibly metric and standard), a ratchet, extensions, possibly a serpentine belt tensioner tool (highly recommended, but sometimes you can use a breaker bar or large wrench), and the new serpentine belt. Gloves are also a good idea.
* Consult your vehicle's repair manual: This is the best resource for specific details and diagrams for your exact engine.
2. Locating and Identifying the Belt:
* Visually inspect the belt: Look for cracks, fraying, glazing, or any other signs of wear.
* Identify the belt's path: Trace the route of the belt around the various pulleys (crankshaft, alternator, power steering pump, air conditioning compressor, etc.). Take note of the order of the pulleys.
3. Loosening the Tensioner:
* This is the most critical and potentially difficult step. The 1991 Chevy pickup likely has an automatic belt tensioner. These are spring-loaded mechanisms that need to be relieved to release tension on the belt.
* Locate the tensioner: It's usually a pulley with a pivot point.
* Use the correct tool: Ideally, use a serpentine belt tensioner tool specifically designed for your truck's engine. This tool will have a socket that fits the tensioner.
* Alternatively (and less ideal): If you don't have the tool, you might be able to use a breaker bar or a large wrench on the tensioner to carefully apply leverage to relieve the tension. Be extremely cautious here; you could damage the tensioner or injure yourself. This often requires someone to hold the wrench while you work the belt off.
* Once tension is relieved: The belt should be loose enough to lift off the pulleys.
4. Removing the Old Belt:
* Carefully work the belt off the pulleys, starting with the loosest pulley. Follow the path you noted earlier in reverse.
5. Installing the New Belt:
* Route the new belt onto the pulleys, following the same path as the old belt. Make sure it sits correctly in the grooves of each pulley.
* Release the tensioner tool or breaker bar slowly. The belt will snap back onto the tensioner pulley as you do.
* Ensure the belt is properly seated: Make sure it's snugly on all the pulleys and not twisted.
6. Re-check and Test:
* Visually inspect the belt: Make sure it's properly seated and not twisted or misaligned.
* Reconnect the negative battery terminal.
* Start the engine: Listen for any unusual noises from the belt. Check for slipping or squealing. If you hear anything unusual, turn off the engine immediately and double-check your work.
Important Considerations:
* Diagram: A diagram from a repair manual is invaluable. It shows the exact routing of the belt.
* Tension: The belt needs to be snug but not overly tight.
* Tool: A serpentine belt tensioner tool is highly recommended to avoid damage and injury.
* Professional Help: If you're uncomfortable with this task, take your truck to a qualified mechanic. It's better to spend money on professional service than to risk damaging your engine or injuring yourself.
This information is for general guidance only. Always refer to your vehicle's repair manual for the most accurate and detailed instructions. Remember, working on your vehicle can be dangerous. If you're unsure about any step, seek professional assistance.
