taikowaza

i have locking stant gas caps for the regular gas tank and the NWMP extended range tank. the standard tank cap fits fine with no leaks. The NWMP tank (which sits under the spare tire, fills via a tube hidden in the wheel well) came with a regular non-locking cap which fits fine, but which anyone could open and siphon out/contaminate etc. The company recommends a certain make of stant gas cap which fits properly (it locks into place) but the seal is not 100%. I can smell gas evaporating out of there, which is a waste of fuel and I can't imagine it being completely safe either.
I'm wondering if there's a way to make a better seal on these locking gas caps? or, would it be better to simply use a non-locking cap, get a better seal, and not worry about siphoning/contam? I like the security of a locking external cap if possible, but this can't be good for mileage either. thanks for helping me decide the lesser of 2 evils...best scenario would be to get a perfect seal on that locking one!

stormin94

Return it to the store, and get another one? I dunno, but I'm thinking of investing in one of those as well. I like the fact that I have a fuel door latch that operates inside the cab, but if you really wanted to, you could open it, and have your way with my gas. With gas prices going up over $3.49, and it's gonna get worse, I don't want anyone steeling my precious gasoline.

taikowaza

hi stormin', thanks for the suggestion! good idea, I also thought that I might have a bad gas cap, but this is the 2nd locking cap I've had on that extended tank fill spout, and both were the same. they lock fine! it's just not a 100% tight seal. If there is any way to beef up the rubber gasket on there, that would be the best. not sure how to do that though. I am trying to decide which is more important, MPG or security of a locking cap.

stormin94

Well, you will more likely see an MPG drop, than someone stealing your gas, and those locking gas caps can be defeated by using a screwdriver to break the lock, but it is a theft DETERRENT. Most theives are after something easy, and if you make em work for it, they might just leave you be. I think if you took the seal off, and maybe put a thin layer of silicone, or some other type of soft gasoline resistant sealer , and then put the seal from the cap back on, maybe that would help, maybe you just have an uneven fit, and a little more mush under there would make it mold to the neck better. And if you put too much on there, you can always dig it out with a knife, or something.

taikowaza

i like that idea stormin', before switching back to the non-locking cap I'd like to add some kind of sealant to the gasket like you suggest. is there a gas-resistant material that I could apply to the rubber that would make it fatter and create a better seal, ideally something that won't come off, that will mold to the rubber and won't flake/get into the filler tube, something that won't contaminate the tank

stormin94

Silicone. But I would wait til it dries to put the seal back on it, just in case you added too much. Most silicone sealer is soft enough to easily mold when it is dry. The way I'm suggesting is to remove the seal, and place the silicone, then replace the seal, in case there is any confusion. Silicone, as far as I know will not dissolve in gasoline, nor will it contaminate the tank, as long as you wait for it to dry before you put it on the neck. I'm nearly certain that the seal between the plastic, and the silicone, and the silicone and the seal will be tight. You probably will not even have to bond the silicone to the seal, as it is soft, and flexible.