Here's a general guide. Specifics may vary slightly depending on your engine size:
Tools You'll Need:
* Socket wrench set: You'll need a socket that fits your spark plugs (likely a 5/8" or 13/16" – double-check your owner's manual). A ratchet and extension will be helpful for access.
* Spark plug socket: This is a special socket with a rubber insert to grip the spark plug and prevent damage.
* New spark plugs: Buy the correct type and heat range for your engine. Your owner's manual will specify this, or you can find the information online using your VIN.
* Wrench: To remove the coil packs or individual wires (depending on your engine).
* Gloves: To keep your hands clean.
* Penetrating oil (like PB Blaster): This can help loosen stubborn spark plugs. Apply it several hours or even overnight before attempting removal.
* Wire brush or similar: To clean the spark plug wells.
Steps:
1. Locate the Spark Plugs: The spark plugs are located on the top of the engine. Access might be slightly tricky depending on your engine. Consult a repair manual or online resources with pictures of your specific engine bay for precise locations.
2. Disconnect the Battery: Disconnect the negative (-) terminal of your car battery.
3. Remove the Coil Packs or Spark Plug Wires:
* Coil-on-plug (COP) system (more likely on a 1998 model): Each spark plug will have a coil pack directly on top of it. You'll likely need a wrench to carefully remove these, often using bolts or clips. Some have a quick disconnect, others might require a wrench.
* Individual Spark Plug Wires: If your engine uses individual wires, carefully disconnect each wire from the spark plug, making note of their placement to ensure correct reconnection.
4. Clean the Spark Plug Wells: Use a wire brush or compressed air to remove any dirt or debris from the spark plug wells. This prevents debris from falling into the cylinder when you remove and install the spark plugs.
5. Remove the Spark Plugs: Using the spark plug socket and ratchet, carefully remove the old spark plugs. If they are stuck, apply gentle back-and-forth motion while turning counter-clockwise. Avoid stripping the threads. If a plug is extremely stubborn, consider using penetrating oil.
6. Install the New Spark Plugs: Before installing the new spark plugs, lightly lubricate the threads with anti-seize compound (optional, but recommended). This prevents seizing in the future. Screw the new spark plugs in by hand until they're snug. Then, use the spark plug socket to tighten them according to the manufacturer's specifications (usually a specific torque value - check your owner's manual or online resources). Do not overtighten.
7. Reconnect the Coil Packs or Spark Plug Wires: Reconnect the coil packs or spark plug wires in their original locations.
8. Reconnect the Battery: Reconnect the negative (-) terminal of your battery.
9. Start the Engine: Start the engine and listen for any unusual noises or misfires.
Important Considerations:
* Repair Manual: A repair manual specific to your 1998 Pontiac Transport is highly recommended. It will provide detailed diagrams and torque specifications for your engine.
* Torque Specifications: Over-tightening spark plugs can damage the threads in the cylinder head. Under-tightening can lead to leaks and misfires. Use a torque wrench if possible to ensure proper tightening.
* Gap: While rarely necessary with new plugs, some may need a gap adjustment. This is only done with a spark plug gapping tool and should be done according to the manufacturer's specifications.
If you're not comfortable performing this task yourself, it's best to take your car to a qualified mechanic. Incorrectly installed spark plugs can cause serious engine damage.
