HELP! Fuel leaking from fuel tank.

[Puff]

Just went outside and there is a puddle of diesel fuel on the ground under the fuel tank. It looks like it’s leaking from a port on the fuel tank module, on top of the tank, that doesn’t have a hose on it—the port is facing in towards the center of the truck. Is this the rollover valve?



I opened the fuel cap and it seems like the fuel has stopped leaking out.



The truck has been sitting all day. It’s hot. I just filled the tank last night.



What’s going on? This can’t be normal?



Could it be that the tank is filled to the top and due to the heat, pressure has built up? Problem is, this is the first time this has happened and it seems like it would have happened before.

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Just checked again. It has stopped leaking. It must have been a pressure buildup. When I first opened the fuel cap I heard a gurgling sound.



Is the fuel cap suppose to vent this excess pressure?



I'm going to take it for a drive and see if things are OK.

 

[B.G. Smith]

Fuel tank leak

Had similal incident the first time I filled my aux. tank. Next morning fuel was dripping from tne tank onto the ground, couldn't really tell where it was coming from but the tank was wet all around the module where the lines come out. I tightened the module retaining nut, ( I sat up under the truck with my head on the passenger side of the driveshaft and used a strong piece of wood, 1"x2" about 2' long and a rubber mallet) haven't seen a leak since. bg

 

[HC]

Fuel from an underground tank would have been quite cool compared to daytime high temperatures, so there might have been enough expansion to cause what you saw.

If I'm filling "up the neck", I try to do it only when I plan to drive at least 20 to 40 miles before shutting down again. Or, if I'm close to home, I skip the "top off" on the fill. For what it is worth, I notice some military vehicles have warnings near the fuel tank and/or a "fill line" that leaves quite a bit of room above the fuel. If you topped off and drove only a few miles, I would say what you saw was "normal".

 

[Puff]

HC: I think you are right. I think the reason I never experienced this before is because the truck stop I usually fill-up at is 20 miles away. I filled-up this time just down the street, and I did fill it up to the neck.



Scared the heck out of me though. Until I realized the fuel was coming from the fuel module, I thought some kid put a nail through the tank or something.



Anyway, all seems fine now. Live and learn. No more necking for me.

 

[KWIKKURT]

Fuel Tank Leak

Puff01,



Just I thought I would tell you. I drilled a hole in my tank to install a second Lift pump fuel line. And could not believe how thick these tanks are. About 3/8" to 1/2" and two kinds of plastic. Now I understand why they don't put factory rockguards on the tanks.

 

[Puff]

Hey, thanks Kurt. That is good to know. Didn't think they were that thick.