Anyone have a leak caused by fuel expansion?

[Troy]

So I always fill my cars up before storing for the winter. A couple years ago the Mach 1 busted a fuel line and made a huge, scary mess. I am storing someone elses Charger and noticed a fuel smell over the weekend. I saw a puddle but nothing leaking - and the puddle wasn't under or even near any lines or low spots in the tank. I cleaned it up and waited to see if anything else happened. Yesterday I was working in the garage and could smell fuel again. I looked under the car and it was dripping steadily out of the frame rail!(?) I assumed it was leaking from the filler tube into the trunk but I didn't have the keys to open it up. I popped the gas cap open and could see fuel about 4" from the top. There were air bubbles and I could hear it gurgling. I went to get some hose to siphon some out but when I got back there wasn't any gas in the filler tube and the leaking had stopped. My garage is heated and I usually keep it at 50 degrees when I'm not there and 60 when I'm working. It has been warm but when I checked the temperature it was just below 70 inside. Would a 10-15 degree change in temperature really cause the gas to expend that much? Could there be something else increasing the pressure? Where else can this assembly leak from?

Troy

[Ghoste]

I've had it happen.

[NHCharger]

When I first bought my 71 in 1995 I filled it up one day about 4 miles from home. When I got home from work the next day my wife said she could smell gas. I checked under the Charger and I must have lost over a quart of gas. The 71's have the four lines out the drivers side to a fuel vapor separator, however the previous owner had disconnected it and just had one line going to the engine and had plugged the others. He must have used bubble gum because the gas was leaking out of the plugged lines.

[Troy]

How much can it expend though? I can't see gas in the tube at all now but it was almost to the top. I've heard that the tube can hold almost a gallon so that's an awful lot of expansion!

My initial thought was that it ran to the top of the tube and came out the vent. If the vent hose was missing it would fall onto the trunk floor.

Troy

[Ghoste]

I've never really measured it or anything like that, just have definitely had it happen a few times.

[moparstuart]

 i have had it happen out the vent tube  but only if the car is really full and a really hot day

[BrianShaughnessy]

I don't fill anything right to the top unless I'm on a roadtrip.

Had a miserable car show experience a few years ago when some old farts filled up their 57 chebbie prior to the show when it was 95 out and the car proceeded to puke a couple gallons all over the pavement NEXT to Black Betty.    I saw both types of Aholes...  1.   the Aholes that thought the F'ing Mopar was leaking gas when it was in fact the POS chebbie... and 2.   The Aholes smoking around the smelly chebbie.

[Budnicks]

I had a wrong cap on a 68 RR it pouched out the sending unit gasket made a feaken smelly unsafe mess in the garage... But it was about 95* or so, in the direct sun with the door open...

[400/6/PAC]

It happened to Me last summer.
That was the only time I ever brought the car home full.
I siphoned a little gas out and no more problems.

[Ghoste]

Probably also depends a little bit on the temp of the fuel when you did the fill up as well?

[Troy]

It was cold(ish) but I don't know the exact temperature. Probably in the 40s or low 50s.

So it's not abnormal then. I'll pop the trunk and see if I can get a better idea of where it's coming from. My R/T would leak from the sending unit seal if I filled it all the way up but I don't recall it ever coming up the tube.

Troy

[Old Moparz]

Stories like this make it obvious that anyone who uses a heating system with an open flame could have a ticking bomb & not know it. A lot of people post about having wood stoves in the shop & that they're "very careful" about how they use it. Something like a gas leak from expansion can happen no matter how careful you are.

Troy, what type of heating system is it in your shop?

Could be time to look if you don't already know.   

[68X426]

Stories like this make it obvious that anyone who uses a heating system with an open flame could have a ticking bomb & not know it. A lot of people post about having wood stoves in the shop & that they're "very careful" about how they use it. Something like a gas leak from expansion can happen no matter how careful you are.

Troy, what type of heating system is it in your shop?

Could be time to look if you don't already know.   

Great advice. 

[Troy]

Believe me, I have worried about that since the Mach 1 sprung a leak - enough to make me reconsider storing the cars with full tanks. I rent the garage so I didn't build it. The furnace is approximately 3 years old and appears to be a regular gas furnace and it has a pilot light. Lots of flames when it kicks on. The good news is that it's 40x60 and both leaks have been on the opposite corner from the furnace. It has been getting into the 70s lately with lows in the 30s so I shut of the furnace completely. The Mach 1 was leaking in the middle of winter though and it was a much bigger leak. I had to air out the garage for a few hours before I could even stay in there long enough to clean up the mess. That was definitely a bomb in the making!

Troy

[Todd Wilson]

I wonder if the barometer and the warm garage had something to do with it. I have seen it happen on really hot summer days..............


Todd

[Old Moparz]

I wonder if the barometer and the warm garage had something to do with it. I have seen it happen on really hot summer days..............

Todd

The plastic gas cans in my garage all seem to swell up like balloons in hot weather. I was talking to one of the mechanics at work about this expansion topic at lunch time. He said that when he used to work for a fuel company that took deliveries from barges on the river, they had expansion lines connected to the tanks that would be empty, but after the day heated up they'd open up one of the valves & could get as much as 10 gallons of gas out of the same line.

[resq302]

Ive had it happen to my charger also.  And the gas was not filled all the way up in the filler neck either.  I think a lot of it has to do with barometric pressure and the outside air temp vs. what the actual gas temp is.  When gasoline turns to vapor, it is expands X amount of times its liquid volume.  http://answers.yahoo.com/question/index?qid=20070608101130AA79rH6&show=7   Another reason why NOT to fill up during the warmest part of the day.

[Brock Lee]

It used to happen to me on hot summer days when I filled up at a local gas station that had their tanks behind the building with no asphalt over them, just concrete. I would fill up, get home, the cold fuel would expand as it warmed and leak all over the ground. I could stop at the first click and it would still do it.

[Paul G]

Happened to me twice. Once on the Harley, filled up the tank on a hot day, cold gas fresh out of the ground, a ways down the road it started coming back out of the filler on to my pant leg. Other time I filled my 73 on the way to Power Tour, hot day, cold gas fresh out of the ground, started puking out of the tank before I could even get the cap back on. Gas expands a lot I would say.

[Troy]

Yesterday was warmer than the other two and there was no evidence of leakage when I stopped by the garage. However, there was gas in the filler tube but I bumped the car a few times and the level went down. Based on the bubbles I'm wondering if there isn't an air pocket in the tank that's expanding? The car is sitting slightly lower on the front driver's side because of where it's parked so maybe that's enough to cover the filler tube?

Troy

[resq302]

Troy,

you could have just hit the nail on the head.  Air certainly expands and contracts also dependent upon the air temp and barometric pressure.  Could be a combination of things too but I'd believe that more of it has to do with the gas expanding due to trying to go into vapor form.  Now if there is an air pocket in there, that would kind of "seal" up the gas and if it were to expand and turn into vapor, it would push any of the liquid gas that is above the air pocket out.

[greymag]

I figured it out a while back on another forum. Gasoline comes out of the ground at 55-60 degrees. At 90 degrees 20 gallons expands a little over 1/2 gallon from 55 degrees. Since it can't compress, it has to go somewhere.

[squeakfinder]

     I don't know why, but it seems vent's just don't always keep up with the vapour. More than ounce I've unscrewed a gas cap an had pressure hiss out of the tank. My wife used to pump gas and had caps practically pop off into her hand. And it didn't seem to matter how much gas was in the tank.

     

[jaak]

When I had my '73 Rallye, I removed the engine to paint it, and plugged the fuel line with a bolt. I came home from work and as soon as I got out of my truck, I could smell gas and it was strong. I walked into my garage (40 x 32, detached) and there was gas covering approximately 1/4 of my floor. It was a hot summer day, and I guess with the expansion, the pressure blew the bolt out of the line and dumped gas all over my floor.

Jason

[Cooter]

Sta-bil added to HALF A TANK...NEVER fill an older car all the way to the neck...You WILL have a mess to deal with.