Loosing gas out of the tank of the Charger?

[Manfred318]

Ok heres my problem. Im loosing gas out of the tank of the Charger ('68) when Im not even driving the car, so I know its not because Im driving like a bat outta hell. Its been happening for a while now, but it only seems to happen on hot days after I fill up. Like today I was leaving to go to work and there it was a nice gassy soggy spot on my asphalt driveway. Ive checked to be sure the vent hose is not all clogged, and its not. It seems its building up too much pressure and blowing gas out of the vent hose. Shouldnt the vent hose keep from pressure building up and blowing gas out of the tank? Its kinda got me bumfuzzled . Any Ideas on what could be causing the problem??

[Ghoste]

Is it dependant on how full the tank is?  My car used to do it if the tank was full and I came to find eventually that it was a split in the vent hose that only opened under the right conditions.  Tank full, hot day in my case.

[ITSA426]

I've got a slightly different versoin of the same problem. 

One of my cars started leaking where the filler neck enters the tank.  The first time, I replaced the gasket with an aftermarket gasket and it lasted about a week.  Then I found the gasket is still available from mopar so I used one of those for a summer before it started leaking in the same place.  I replaced the filler tube and installed a new mopar gasket.  Still leaks particularly on warm days.  The cap is vented and working.  The tank was refurbished.  I was thinking there is a problem with alignment where the tube enters the tank but there is no visible sign of any body problem and the install is pretty rigid.  There are no splits in any of the rubber tubes and all connections are tight.

The leak is at the bottom of the connection where fuel enters the tank.  I've also used a fuel proof grease to install the tube into the grommet.  That will stop the leak for a while.

Now another car has started leaking in the same place so I'm beginning to wonder if it's the brand of gasoline.  Anybody ever heard of this problem?

Also, if your tank is full the gas will expand and run out the top of the filler neck on a hot day.  I've learned to keep the tank level low unless I'm using the car.  Any ideas?

[Manfred318]

Is it dependant on how full the tank is?  My car used to do it if the tank was full and I came to find eventually that it was a split in the vent hose that only opened under the right conditions.  Tank full, hot day in my case.

Hmm... never thought about a split in the hose. Mine does the exact same thing. Yea it depends on how full the tank is and how warm it is. If I fill up it leaks out until I use up about a half tank then it will not leak any more. I'll try replacing the vent hose.

[UFO]

I have heard that the ethanol in the gas is breaking down the rubber in fuel lines,so I guess it could attack the seal when its full.Constantly being splashed on while driving will just take a little longer.

[ITSA426]

I'm thinking ethanol, or one of the other additives might be the problem.  I think I'm going to try to leave it around a half tank of gas for storage and only fill it when it's going on long enough trip to burn out the gas.  Fortunately those sending units and gas gauges are deadly accurate.

[Ghoste]

The downside to that is that if you store it frequently with a partial tank of fuel, it's an excellent way to get condensation forming inside the tank and all of it's attendant problems.

[mopar0166]

did you check the small rubber hose that connects the sending unit to the fuel line

[ITSA426]

Mine is leaking at the bottom of the tube where the fuel enters the tank. 

My experience with fuel tank condensation is pretty minimal, especially since so much of the new fuel contains ethanol; which, I understand, tends to hold water in suspension.  It's been a long time since I got a measurable quantity of water out of a tank, even in the cars I've parted.

[Ghoste]

That makes sense too I suppose.  I guess for me, it's an old habit to keep a stored car full of fuel so I'll continue doing it that way but I can see the ethanol/water bit.

[BlueSS454]

I'm kinda glad I'm not the only one having this problem too.  I too noticed it on particularly hot days after filling up.  Everytime I have filled the car up, it's been pouring gas on to the ground.  I've been keeping the tank around half full just because of that.  At first I thought it was simply coming out of the vent hose on the sending unit, but it's clean there.  I'm gonna go under the car tomorrow and check the filler neck into tank area and see what I find there.

[Manfred318]

I'm kinda glad I'm not the only one having this problem too.  I too noticed it on particularly hot days after filling up.  Everytime I have filled the car up, it's been pouring gas on to the ground.  I've been keeping the tank around half full just because of that.  At first I thought it was simply coming out of the vent hose on the sending unit, but it's clean there.  I'm gonna go under the car tomorrow and check the filler neck into tank area and see what I find there.

Ya know Ive crawled up under mine and it doesnt look as if the gas is comming from the filler neck seal. At first thats where I thought mine was leaking from. Ive even replaced the seal twice now and it still leaks, not to say the last seal hasnt went bad but it was just replaced not even a year ago.

[resq302]

I have the same problem with my charger.  On hot or humid days the gas tends to expand more due to the make up of the newer gasses out there.  With it expanding, it needs to go somewhere.  On mine, it ends up coming out the vent and running down the rail section of the unibody.

The same thing happens with our el camino only it goes out of the filler neck and down onto the gas tank and then down onto the ground.