Gas expanded and overflowed over night?

[65barracudaLA]

I got gas around 10pm last night and went straight home. When I went outside around 2pm I noticed that there was a puddle of gas under my '65 Barracuda and it was still dripping. It was coming out above from where the filler tube goes into the tank.

When I took off the gas cap, gas was gushing out. Not just a drip, the gas must have been sitting behind the cap. Some years ago I replaced the paper gasket in the cap with some chemically resistant rubber, so it seals pretty good.

So my question is: How is that possible? The gas station is level and so is my parking space (the photo is not at my parking space). Currently it's about 65 degrees during the day and about 45 at night. Could that 20 degree difference in temperature make the gas expand so much that it came up the filler tube? Have you ever had that happen? I can't think of anything else?!

 

[fishmens67]

It sounds like a venting problem.

 

[RAT ROD AL]

That's not a good thing with the whole area in a blaze !

 

[67Dart273]

Not a vent problem, no vent problem could possibly cause that. I think the OP had it right. Maybe you just got "lucky" and got a nozzle that has a poorly operating shut off, and somehow just filled it quite full.

EDIT LOL I was not thinking. A PLUGGED vent could allow this problem to happen, but the vent would at least allow the fuel to spill out on the ground, rather than all over the paint/ out of the filler.

What is the temp difference from the gas station to your garage? Heated garage?

As "tall" as the fillers are on Barracudas and even the other A bodies, that doesn't happen often. I've owned 3 B bodies, a long time ago. The fillers on them are barely above the fuel tank "roof"----out behind the license plate. I used to "wash" my rear plate quite often.

 

[dadsbee]

Cold ground tank vs outside temp..

 

[Lefty71]

Agree with post #2. Gas doesnt expand.....but it can be pushed pretty good with the help of some air warming up.

 

[65barracudaLA]

That's not a good thing with the whole area in a blaze !

No ****!

 

[dadsbee]

Gas does expand! Why it's sold with the disclaimer of "volume corrected to 15C".

 

[65barracudaLA]

Not a vent problem, no vent problem could possibly cause that. I think the OP had it right. Maybe you just got "lucky" and got a nozzle that has a poorly operating shut off, and somehow just filled it quite full.

What is the temp difference from the gas station to your garage? Heated garage?

As "tall" as the fillers are on Barracudas and even the other A bodies, that doesn't happen often. I've owned 3 B bodies, a long time ago. The fillers on them are barely above the fuel tank "roof"----out behind the license plate. I used to "wash" my rear plate quite often.

So I looked into it and apparently gasoline expands 1% with every 15 degrees of temperature. I think it's an 18 gallon tank, so 0.18 gallons or 23.04 fl oz. It was 45 degrees last night and 65 degrees when it overflowed (not unusual in California "winters"). It was 20 degrees not 15 degrees warmer, so roughly a 1.3% increase, which brings it to 29.952 fl oz, which is quite a bit.

The vent has a bit to do with what happened. Someone had removed the vent tube and put just some rubber fuel line in its place. Not even with a hose clamp, just a zip tie around it. So I when the gas vent up towards the gas cap it went past the hose and zip tie, ran down the filler tube and that's were I saw it dripping out.

I will investigate further, but it appears to be a combination of unusual circumstances. I will definitely fix that vent tube situation!

 

[Dana67Dart]

. Gas doesnt expand....

I beg to differ...

Gas is a liquid and as it warms it WILL expand in volume that's physics.


Ever had a sealed gas can in the sun or even in a warm garage.

My garage will raise 20 deg between dat and night. Gas can expands during the day and the shrinks during the night.

I had a 56 Ford pickup. Gas tank in the cab.

If I filled the tank in the morning and then it sat through the day I would come out and have a cab full of gas fumes

The fuel in the gas station was cold from being in an underground tank then the truck cab would warm up and the fuel would expand enough to fill the filler neck and leak past the gasket. It would then dribble down the filler neck into the cab and down.

Turning them at key was always a thrill


For the OP....

A thoughts...

1. Don't fill the tank till it clicks, purposely underfill the tank by a gallon or so and see if it happens again.

IMHO

If it did not leak when filled then the ONLY thing that can cause the fuel level to increase is expansion from temperature change.

 

[65barracudaLA]

I beg to differ...

Gas is a liquid and as it warms it WILL expand in volume that's physics.


Ever had a sealed gas can in the sun or even in a warm garage.

My garage will raise 20 deg between dat and night. Gas can expands during the day and the shrinks during the night.

I had a 56 Ford pickup. Gas tank in the cab.

If I filled the tank in the morning and then it sat through the day I would come out and have a cab full of gas fumes

The fuel in the gas station was cold from being in an underground tank then the truck cab would warm up and the fuel would expand enough to fill the filler neck and leak past the gasket. It would then dribble down the filler neck into the cab and down.

Turning them at key was always a thrill


For the OP....

A thoughts...

1. Don't fill the tank till it clicks, purposely underfill the tank by a gallon or so and see if it happens again.

IMHO

If it did not leak when filled then the ONLY thing that can cause the fuel level to increase is expansion from temperature change.

I was wondering if that had ever happened to anyone. So it's plausible.

I've been filling up the tank all the way (to the auto shut off) because I've been tracking my gas mileage to compare the changes I'm making to ignition, timing, carb, etc.

I will remember to not fill it all the way at night. Also, I will fix that vent issue! My homemade gas cap gasket was not leaking one bit haha.

 

[Killer6]

Gasoline 100% expands & contracts with temperature, the question is, how did You manage to get it that full? The vent tube may very well be plugged, which would trap pressure in the tank as the volatile gasses try to expand at a rate geater than the liquid, if the liquid reaches a point it can seep out the pressure will make sure of it.
I experienced a gasoline overflow years ago in the private shop I worked at. Customer brought work van over for service the next day, & We pulled it in on the floor mid-shop before closing up, outside temps were similar to current ones(15-20°F), & left. Next morning there was a puddle of gasoline almost half the size of the van under it, We opened both doors & I killed the furnace, don't know how that place didn't blow to this day. Called the guy, "Oh yeah, I filled 'er up across the street before droppin' it off", oye........

 

[AJ/FormS]

Keep in mind that as you are driving, and consuming fuel, the vent system allows outside air to enter the tank. If the pressure does not equalize as you are driving, the Fuel pump will try to collapse your fuel tank or, if it cannot do it, then the engine will quit running for lack of fuel.
The vent system has to work in both directions.

 

[George Jets]

You may need a vented gas cap.

My '67 Dart had a vent tube up out of the tank, followed to up under the quarter, back down again through the trunk floor, and out to the atmosphere.

Vented Tank

Yeah you don't want to fill your tank plumb full.

☆☆☆☆☆

 

[mopar head]

Yep it do. Expand with heat. I found out when I filled my welder up in the morning, it sat till noon doing other work when I went out to start it I noticed gas leaking out. I`d fill to the bottom of a 4.5" diameter X 2.5" deep neck and it pushed out of that much space.