I didn't vent my fuel tank

[hogfarm]

I as things go,I have forgotten to vent my fuel tank.There is a thread hole in the top that I plugged,where can I find a 3/8" NPT vent

[mongocanfly]

you don't need to vent it right on the tank...run a hose from tank up to the frame rail and then install your vent...summit has a big selection and you may want to look for a rollover protection style valve

[_Ogre]

i'll say you don't want to vent it on the tank
i have a side fill in the fender, i ran a hose up the filler neck and looped the hose high
also have a inline fuel filter near the tank fitting to prevent any dirt from getting sucked in
the fuel filter was recommended by nolimit, the tank manufacturer

i still get a little gas venting on warm days if i don't watch the fill
typing this made me think i should drill a vent hole in the non-vented cap to use the filler neck capacity to prevent venting gas

[Black_Sheep]

Under bed tank, the vent is much higher than the tank to avoid the possibility of fuel sloshing out.

[mr48chev]

I was going to say just about what black sheep showed but run it up inside the stake pocket an have a filter of some sort on it. Even a cheap plastic fuel filter to keep any dirt or dust out. I like his rounded over end thing too. It needs to vent high enough so that there is no chance of gas spilling out parked on an incline when the tank is full.

[Jesse Z]

I have vented fuel tanks by drilling microscopic holes in the cap - so tiny that only air can pass. Worked great and I never had any fume or leakage problems.

If however you feel you need a "real" vent, TANKS Inc has a selection, including some with integral rollover valves.

[mongocanfly]

and they do make vented caps...

[LEEVON]

I tried 3 different vented caps, none worked and my engine starved for fuel. I put 1/8npt nipple in the filler neck, ran a hose loop up high in the cab corner, then back down through the floor, into the frame and back to the rear of the truck with a one way fuel filter. No more issues, no smell either.