The 1998 Lincoln Navigator is a complex sport utility vehicle with a lot of luxury features. The truck is known for its large roomy interior and powerful engine. To ensure the engine is running at peak performance, change the fuel filter to keep sediment and debris out of the engine. The recommended interval for changing out the filter is 30,000 miles. The new filter will also help to improve fuel economy as well as performance.
Open the hood to access the Schrader valve. The Schrader valve is located toward the top of the engine and has a red cap over it. Pull the red cap off the valve. Press the center of the valve with a flat-tip screwdriver to release the fuel pressure. Have a rag handy to clean up any fuel that sprays out of the valve.
Disconnect the negative cable on the battery with a line wrench. The negative cable is the black cable.
Locate the fuel filter under the driver side back door. Trace the fuel line to a black box with an access panel.
Open the access panel toward the driver side frame rail and the panel will pop off. This will expose the fuel filter.
Separate the tabs on the protective clips on both sides of the filter. Slide the protective clips back to expose the fittings holding the fuel line to the filter.
Disconnect the fittings on both sides of the filter by placing the quick-disconnect tool over the end of the fitting. Pull the tool toward the filter to release the fittings. Repeat for the remaining side.
Pull the filter away from the truck by pulling it away from the mounting bracket. Replace with the new filter. Ensure the arrow on the filter is pointing toward the front of the truck. The arrow designates fuel flow.
Push the fuel lines on to the filter. The lines will lock once pushed on far enough. Slide the protective clips over the fittings until they lock in place. This will prevent the fuel line from accidentally slipping off the filter.
Position the access panel back over the box. Ensure it is closed.
Connect the battery by securing the negative cable on to the battery. Tighten with a line wrench to secure the cable to the terminal.
Turn the ignition to the "start" position. Leave it in this position for three seconds to allow the fuel pump to prime itself. The fuel system has accumulated air in the fuel lines. Once all the air has been pushed out, the truck will start.
Allow the truck to idle for five minutes. Open the access panel to observe the filter for any leaks.
