The 7.3-liter Navistar diesel engine was the largest power plant available in the 2000 one-ton Ford vans. While the V-8 and V-10 gasoline engines may be adequate for some owners, the turbocharged 7.3-liter diesel is the best choice for those hauling or towing the largest loads. While the 7.3 is a good engine, there may be some problem areas that will eventually need attention. One of these is a leaky drain valve on the combination fuel bowl and water separator. Rebuilding the drain valve should keep diesel fuel from leaking on your driveway.
Things You'll Need
- 13 mm deep socket
- 3/8-inch-drive ratchet wrench
- 3 foot length rubbing tubing
- Drain pan
- #20 Torx bit
- 1/4-inch socket
- 1/4-inch ratchet wrench
- Hooked tool
- #8x32 machine screw
- Torque wrench
Remove the two retaining nuts on the plastic engine trim cover with a 13 mm deep socket and ratchet wrench. Pull the wire routing clip straight off the passenger side of the cover. Lift the cover straight up and remove it from the engine compartment to reveal the fuel bowl.
Push a 3 foot length of rubber tubing onto the drain tube -- visible on the underside of the engine -- that comes from the drain valve on the back side of the fuel bowl. Route the opposite end of the hose into a drain pan placed on the floor under the engine.
Turn the yellow drain valve lever -- located on the back side of the fuel bowl -- one-quarter turn clockwise to open the valve. Allow the fuel in the bowl to empty into the drain pan. Close the valve. Remove the rubber tubing. Remove the drain pan from under the van.
Pull the drain tube -- located just below the yellow lever -- straight off the back side of the drain valve and push it slightly to the side. Use care when doing this as the drain valve is made from plastic and may break easily.
Remove the four drain valve retaining screws -- two on each side of the drain tube outlet -- using a #20 Torx bit, 1/4-inch socket and a 1/4-inch-drive ratchet wrench. Hold the yellow lever in place while removing the drain valve from the fuel bowl. Make a note of the position of the yellow lever and remove it from the top of valve.
Pry the two rubber O-rings from the backside of the drain valve assembly with a small hooked tool. Pry out the small piece of white plastic -- used to strengthen the valve core -- at the end of the white valve core with the hooked tool. Use care not to lose the small check ball located within the core. Thread a #8x32 machine screw a few threads into the core where the plastic was removed. Use the end of the screw as a handle to pull the core out partially. Pry the O-ring from the core. Press a new O-ring that has been lubricated with diesel fuel into the groove. Push the core back into the valve assembly and remove the screw. Push the small piece of plastic back into the end of the core.
Push two new O-rings that have been lubricated with diesel fuel into the backside of the drain valve assembly. Place the yellow lever in its original position on the valve. Position the valve back to the fuel bowl and replace and tighten the screws finger-tight. Tighten the screws to between 5 and 8 inch-pounds with a torque wrench.
Push the drain tube back onto the outlet on the drain valve. Turn on the ignition key, but do not start the engine. Wait a few seconds for the fuel pump to stop running, then turn the ignition key off. Repeat this two more times. This procedure refills the fuel bowl with fuel.
Start the engine and check the drain valve for leaks. Shut off the engine and replace the engine trim cover. Push the wire routing clip back into the cover.
Tips & Warnings
- Use care not to drop the Torx retaining screws in the engine valley between the cylinder heads. If you do, use an extending magnetic tool to retrieve them.