Gas Tank Overflow?

[speedaddict]

On my 39 Chevy, there's an overflow for the gas tank at the very top of the tank. Is that supposed to be plummed to an over flow tank or back into the tank? Don't know what to do with it but its leaking fumes all in the garage. Not good when the pregnant wife or the 2 year old go in there.

speedy

[porknbeaner]

An overflow is just that an overflow. What good would it do to plumb it back onto the tank?

That is probably a vent. If your tank isn't vented when you're running the motor it will pull into a vacuum or try and you won't be able to get gas out of it.
Put a vented cap on it and plug the hole. If you don't do that at least run a line from the vent on the tank to under thew car somewhere and put an inline fuel filter on the end of it. That way you won't be sucking crap up into the tank when you are running down the road and the tank breaths.

Non of that will get the gas fumes out of the garage but it will make it closer to right.

[Petejoe]

By plugging a ventilated fuel tank, you will implode the tank the next time you run low on gas. The fuel pump will cause suction and cave in the tank.
I find it hard that your getting much fumes from a simple vent tube. My feeling is you have a leak on either the fill or vent tubes or the tank itself.
And please remove that car from the garage before someone gets hurt.

[Slide]

I don't think Chevies had these back as ar as 39, but just in case...

My 52 has an extra tube coming out of the tank right next to the filler neck. THis thing is about 7/16 or 1/2 inch diameter, and it has a rubber hose going up to the other end of the filler neck, just below the cap. THe purpose of this is to allow air to escape from the tank while you are filling it. I tried plugging these lines off, but I could barely crack the pump nozzle open to fill the tank, otherwise it would backflow. Felt like it would take 30 minutes to fill a 16 gal. tank! Anyway, I hooked it all back up, and it worked very good. This deal is separate from the regular vent from the top of the tank.

[Deyomatic]

Also, if your tank isn't vented, when you fill it, the air inside will have nowhere to displace itself, since the only way out is being plugged by your nozzle. What happens is a scary eruption of gasoline, spraying all over the person that is trying to fill the tank.
I've seen this first hand.

[Flexicoker]

On that vent, attach an electric fuel pump and plumb the line into your exhaust, then rig up one of those flame thrower setups, now at the end of the exhasut pipe place a bucket full of water which you will then boil with the flame thower to us to skin your cat.

[Slag Kustom]

run a piece of steel 3/8 line to the top of the fill tube and run a vented cap. if there are too many bends you can use semi ridged fuel hose.

[BELLM]

First I would get the carout of the garage. If you have a gas water heater your house will explode.

[delaware george]

don't worry if the heater is elevated....gas fumes are heavier than air and 19 inches off the floor is usually good