Im new to the diesel world. I have a 2000 350 cc sb. I have noticed a fuel leak one day after a family trip. I looked into it and it is not the fuel water sep valve. I bought a new one but when i went to replace it there is no fuel just sitting on top of the motor between the fuel water seprator and the turbo pedestal, or any signs that their was fuel there. if i look under the truck is is draining onto the top of the axel. I looked at all fuel lines that i could and see not damage. Has anyone had a problem like this and can send me in the right direction to fix it. I am in the military and if i take it to a mech they charge out the butt for anything. I have deceant mechanical knowledge. Any help is much apperciated. Thanks!!

 

sounds like the fuel drain valve, is leaking internally, which will cause the leak to go thru the drain tube, and dump on the axle.

 

The drain tube was dry as well. the only time it became wet with fuel i craked the valve. I drained the bowl last night drove to work sat idle for about 10 minutes, with no fuel leak. Last night i lost about a pint of fuel in 5 minutes at idle. Could if the engine is hot or cold play a factor.

 

Clean everything(valley, frame etc) up with some simply green and a spray bottle of water. DO NOT USE A GARDEN HOSE UNDER YOUR HOOD. Maybe you can use some brake parts cleaner but keep it off of all of your electrical connectors.
You will then be able to very easily see where the leak is coming from. It is probably a fuel line coming from the fuel bowl and going to the fuel gallerys on each head. There is a line on the passenger side valley that has a clamp about mid way from the fuel bowl to the rear of the passenger side head that holds the fuel line down. It is a usual item to wear thru the line and cause it to leak. You really have to be on top of the engine and have that stoopid plastic cover(mounted above the fuel bowl) out of the way to see it.
Take the stoopid plastic cover off and look closely at all of the lines coming out of the fuel bowl for a few minutes after the truck is warm to find the leak.

Do you have a lift kit or a leveling kit on your body that jacks up the rear and therefore moves the tilt of the engine forward instead of back? This would change the flow of the fuel when it leaks.
Dwayne

 

When the fuel drain begins to leak it usually first leaks only when cold.