How to Replace Spark Plugs in a Lincoln Navigator

Lincoln Navigator engines require spark plugs to ignite the gasoline. The Lincoln Navigator owner's manual suggests that all spark plugs be cleaned every 30,000 miles and be replaced every 100,000 miles. Replacing old spark plugs in a Lincoln engine helps the engine use less gas and run more efficiently.

Things You'll Need

• Spark plug socket
• Socket wrench with extension
• Silicone dielectric compound
• New spark plug
• Tension tester

Instructions

1. Allow the Lincoln Navigator engine to cool. The easiest way to do this is to park the vehicle in a shady area and raise the hood.

2. Find the spark plug wires. The location of the spark plugs varies greatly between different year models, but more often than not, the plugs are placed along the sides of the engine.

3. Twist the spark plug wire 180 degrees in each direction to release the boot from the spark plug. Pull back on the boot to remove the spark plug wire.

4. Use the spark plug socket and wrench to remove the old spark plug from the well.

5. Spray the silicone dielectric compound on the threads and the connector on the top of the new spark plug.

6. Insert the new spark plug into the socket and screw it into the cylinder well. Do not tighten it too tight. Test the spark plug tension with the testing tool. Depending on the size of the engine and spark plug, the spark plug tension will range between 13 and 25 foot pounds.

7. Continue replacing the rest of the spark plugs. Replace only one spark plug at a time to avoid crossing the plug wires. When complete, replace the negative battery cable.