Tools You'll Need:
* Socket wrench set: A 3/8" drive set is recommended. You'll need a socket that fits your spark plugs (usually 5/8" for most Ford applications). A 1/4" drive can work, but a 3/8" will provide more torque control.
* Spark plug socket: This isn't a regular socket; a spark plug socket has a rubber insert to grip the spark plug without damaging it.
* Extension: Several extensions may be needed to reach the rear plugs comfortably.
* Wrench or ratchet: To turn the socket. A ratchet will be much easier.
* Torque wrench: Crucial for tightening the new spark plugs to the correct specification. Over-tightening can damage the threads, and under-tightening can lead to misfires.
* New spark plugs: Purchase the correct type and heat range for your engine. Check your owner's manual or a parts store for the correct specification. OEM (Original Equipment Manufacturer) plugs are a safe bet.
* Gloves: To protect your hands.
* Shop rags or paper towels: To clean up oil or dirt.
* Penetrating oil (like PB Blaster): This can help loosen stubborn plugs. Apply this a few hours before you begin the work.
* Optional: Coil pack removal tool: This can make removing the coil packs easier.
* Safety Glasses: Protect your eyes from flying debris.
Steps:
1. Disconnect the Negative Battery Cable: This is essential for safety.
2. Locate the Spark Plugs: They are located on top of the engine, usually one per cylinder. The 4.6L and 5.4L V8 engines have 8 spark plugs.
3. Access the Spark Plugs: You might need to remove some components to access the spark plugs, such as the plastic engine covers, air intake, or even some wiring harnesses (depending on the location of the plugs). Take pictures as you go to help remember how to reassemble everything.
4. Remove the Coil Packs (if applicable): On many Ford Expeditions, the spark plug wires are attached to coil packs. These coil packs typically either unclip or have a few bolts holding them in place. Carefully remove and set them aside, ensuring you remember their correct orientation. Consider taking pictures.
5. Remove the Spark Plugs: Use the spark plug socket and ratchet to carefully remove the old spark plugs. Do not force them! If they are difficult to remove, apply more penetrating oil and let it sit for a few more minutes. If a plug breaks off, you'll likely need professional help.
6. Inspect the Old Spark Plugs: Check the condition of the old spark plugs to assess the health of your engine. Look for wear, fouling, or damage.
7. Clean the Spark Plug Wells: Use compressed air or a shop rag to carefully clean any dirt or debris from the spark plug wells.
8. Install the New Spark Plugs: Carefully hand-thread the new spark plugs into the wells, then use the spark plug socket and torque wrench to tighten them to the specified torque. Never over-tighten!
9. Reinstall the Coil Packs (if applicable): Carefully reattach the coil packs and any other components you removed.
10. Reconnect the Negative Battery Cable:
11. Start the Engine: Check for any misfires or unusual noises.
Important Notes:
* Torque Specifications: This is critical! Over-tightening can strip the threads in the cylinder head, requiring expensive repairs. Under-tightening can cause misfires. Look up the correct torque specification in your owner's manual or a reliable repair manual.
* Gap: In some cases, the spark plug gap may need to be adjusted before installation. Check your owner's manual or the spark plug packaging for the correct gap.
* Professional Help: If you're not comfortable performing this task, take your vehicle to a qualified mechanic. Improperly installed spark plugs can cause significant engine damage.
This guide provides general steps; specific procedures might vary slightly depending on your vehicle's model and year. Always consult your owner's manual for the most accurate and up-to-date information.
