Fuel tank roll-over vent problems...

[steved]

Well, my roll-over valve/valves are leaking. I accidentally left the transfer pump on this past trip to TX... must have "popped" one or both of the roll-over vents as I pushed fuel out the vent hose (I have the vents tee'd into a single hose). I find this weird as I have a return line between the two tanks that should have allowed the fuel to simply return to the aux tank...



Now, when I leave my aux tank siphon into the main tank, it drips fuel out of the vent hose if I stop for any length of time.



I have thought about blowing some compressed air through the lines (with the filler cap off) to see if I can re-seat the roll-over valves?? I think those valves can be replaced can't they??



Any ideas what I should do?? As it stands right now, I have to keep the aux tank line valve closed to prevent dripping fuel... my only alternative is to replace the 1/4-turn valve with a low-cracking pressure check valve to prevent the siphoning (forcing me to pump fuel across instead of siphoning)...



steved

 

[B.G. Smith]

I'm piped up kinda like that but have never had any trouble with the roll over valves leaking. I did have the fuel sending unit/pickup module leak one time and I tightened the big nut and never had any more leaks. That was on a 99 which I ran for 120,000 miles. I'm sure you have checked it but could the fuel be leaking out on top of the tank and just wicking down the hose when you are stopped? I am piped up with a filter, transfer pump then a 12v shut off valve in the line to the main tank. I have an open return line to the aux. tank and have pumped until fuel returned to the aux. many times. I do have my pump switch run through a one hour timer so it will shut off if I forget it. If it is the roll over valve/valves leaking, I think a little air like you said might help. Might be a bug in it? bg

 

[steved]

I know the fuel is leaking from the roll-over valves... I can see it dripping from the filter I have in the end of the hose. I piped the roll-overs to a filter to keep from sucking a bunch of garbage into the tank.



I'll try the air first, then explore my other options...



steved

 

[steved]

OK, this might have been a temporary issue. Seems to have stopped now, but here's my theory:

I think I over-pressured the valves and pushed fuel out into my 10+ feet of line and filter assembly on the rollover vents when I accidentally switched my pump on...

I think the valves were working normally after the over-pressure, and it was just pushing fuel that was still in the line and filter out. I never really lost more than maybe a couple tablespoons at anyone place (you know how diesel spreads when it hits a flat surface)...

steved