A sealant that is impervious to gas?

[The Swed]

Is there a sealant that is impervious to gasoline? I would to seal off the out side of the fill tube grommet to prevent gas from getting to the cab.

Thanks

[GASoline71]

Or just don't fill the tank full or make hard right hand turns.

J/K...

Gary

[The Swed]

I just knew someone was going to poke me about this and a vented cap will most likely leak but I'm still taking the those corners hard and fast!

[SS Tim]

Anything I can think of, like PRC or ProSeal, is going to show .
But you could try a tight fitting "O"-ring on the filler neck below the cap and above the gasket to act as a drip stop. It would also help keep fuel off the body during one of those fueling overflow moments.

[88Ironduke]

Just an option that I have not tried.... But when working on aircraft integral fuel tanks we use a sealant called B-2, also comes in a variants including B-1/2(B-half). Its a two part sealant and can be purchased on the internet. It mixes in a tube (takes about 50 strokes to fully mix it) and mixes the entire tube at one time. You typically have a about 20-30 minutes to work it and can set up can be 2 hours to 12 hours@70'F depending what kind you buy. Once mixed it doesn't matter, use a little or lot but the whole thing will harden up. Its stays pretty pliable even when cold, little shrinkage but its expensive. Probably about 40 bucks for a small tube the size of a large tube of toothpaste. I've never fixed a gas tank or filler neck with it but it works great in a kerosene/aviation fuel environment.

88Ironduke

[franken]

I think a quality gasket sealer or form a gasket will withstand a bit of gas. Years ago I sealed holes poked in a gas can, and the tank on my 69 3/4 ton w/ that stuff.
You can also get some repros of the original rubber part, but Asian rubber doesn't like direct sun.

[Greasey Harley]

The Right Stuff; I don't know if I would put it on the outside of my truck, but it will seal up [dang near] anything!

[Custom/Ten]

this says gas resistant

[dirtyjim]

before trying to seal the grommet I would make sure the tank is lined up where the filler neck centers up on the hole in the cab. there is a little adjustment on the tank.
what is the condition of the grommet? if its new and the tank is lined up I don't see how gas would get past it, at least on my truck.

when I first bought my truck I had the same problem, a new filler neck grommet and aligning the tank stopped it

[Fatherflash]

Originally Posted by 88Ironduke

Just an option that I have not tried.... But when working on aircraft integral fuel tanks we use a sealant called B-2, also comes in a variants including B-1/2(B-half). Its a two part sealant and can be purchased on the internet. It mixes in a tube (takes about 50 strokes to fully mix it) and mixes the entire tube at one time. You typically have a about 20-30 minutes to work it and can set up can be 2 hours to 12 hours@70'F depending what kind you buy. Once mixed it doesn't matter, use a little or lot but the whole thing will harden up. Its stays pretty pliable even when cold, little shrinkage but its expensive. Probably about 40 bucks for a small tube the size of a large tube of toothpaste. I've never fixed a gas tank or filler neck with it but it works great in a kerosene/aviation fuel environment.

88Ironduke

88Ironduke is correct. This stuff is terrific. We also use it all the time and works very well. You can also use AMS-S-8802 to seal a leaking fuel tank. This is the same stuff used to seal aircraft fuel tanks. Can be purchased many places....aircraft spruce, McMaster Carr, ebay.