Anyone else have fuel pour out the vent tube!!???

[steve340]

If you install a vented gas cap you will most likely get a fuel leak from the cap. No good.
I tried reversing the tubes still did it. Made sure no tubes were blocked - no good either.
The tank is vented to atmosphere (it has to be for the fuel pump to work) so the fuel smell while parked could be just fumes coming off the fuel and gathering under the car as fuel vapour is heavier than air. There is no evap canister on a 1968 like a modern car would have to capture the fumes. My car did that and it would puke out and stink after being parked a while.
Yours sounds like the same thing I had. I thought it is OK all old cars are a bit smelly.
My gut felling was the smell was too strong and I was worried about the fuel smell and it turned out I was right - there was a problem.
Is the fuel smell in the garage stronger than you are comfortable with?
Do you get a fuel leak from the passengers side rear chassis rail where the other tube goes to?
Fuel drips out or may be trapped in the chassis rail down by the front of the leaf spring.
Do you ever occasionally notice a smell of fuel for a minute or two and then it disappears when you are driving along the road?

 

[Bbodycomeback]

I had a 69 RR with the same problem switched to a vented gas cap with no problems but it was always parked usually on a level surface and the tank did not stay full very long after a fill up anyway .

 

[koosh]

If you install a vented gas cap you will most likely get a fuel leak from the cap. No good.
I tried reversing the tubes still did it. Made sure no tubes were blocked - no good either.
The tank is vented to atmosphere (it has to be for the fuel pump to work) so the fuel smell while parked could be just fumes coming off the fuel and gathering under the car as fuel vapour is heavier than air. There is no evap canister on a 1968 like a modern car would have to capture the fumes. My car did that and it would puke out and stink after being parked a while.
Yours sounds like the same thing I had. I thought it is OK all old cars are a bit smelly.
My gut felling was the smell was too strong and I was worried about the fuel smell and it turned out I was right - there was a problem.
Is the fuel smell in the garage stronger than you are comfortable with?
Do you get a fuel leak from the passengers side rear chassis rail where the other tube goes to?
Fuel drips out or may be trapped in the chassis rail down by the front of the leaf spring.
Do you ever occasionally notice a smell of fuel for a minute or two and then it disappears when you are driving along the road?

I'm not sure about a 68 , but I dint have any vent tubes near or in a chassis rail.....my 69 has a long one up into the trunk and dumps back down out if the trunk, and a short one that curls up then down next to rest of tank....

 

[chtampa]

I'm not sure about a 68 , but I dint have any vent tubes near or in a chassis rail.....my 69 has a long one up into the trunk and dumps back down out if the trunk, and a short one that curls up then down next to rest of tank....

I believe the one that goes through the trunk is going into the frame.

 

[koosh]

I stand corrected....it certainly does go back down into the frame.....
Sorry guys....

 

[chtampa]

I stand corrected....it certainly does go back down into the frame.....
Sorry guys....

If it happens again you will be set back to the "A" Body class.

 

[koosh]

 

[koosh]

Ok........I want all who replied here....to sit down grab your favorite beverage and get ready for a great laugh......
When I said I got up this morning a smelled all this gas fumes in the garage, it was pretty strong.....
BUT--- after a little more exploring, found my son's motorcycle sprung a gas leak with a cracked hose near the shutoff valve...he never closed valve after parking in my garage.
Hence the strong fumes, and NOT from the Roadrunner!
I know I had an issue yesterday from the short vent tube, but not this time! Talk about coincidences!
Laugh it up boys, I did !!!
I DID install a taller/longer short tube, so hoping that eliminates the full tank leak syndrome.....
Ps.... thanks for all the help.

 

[Cojohnso1]

Ok........I want all who replied here....to sit down grab your favorite beverage and get ready for a great laugh......
When I said I got up this morning a smelled all this gas fumes in the garage, it was pretty strong.....
BUT--- after a little more exploring, found my son's motorcycle sprung a gas leak with a cracked hose near the shutoff valve...he never closed valve after parking in my garage.
Hence the strong fumes, and NOT from the Roadrunner!
I know I had an issue yesterday from the short vent tube, but not this time! Talk about coincidences!
Laugh it up boys, I did !!!
I DID install a taller/longer short tube, so hoping that eliminates the full tank leak syndrome.....
Ps.... thanks for all the help.

Definitely post if this effort helps?

 

[Wietse]

When i replaced my fuel pickup on my '69 Coronet i blocked off the short vent tube.
Why does it have 2 vent tubes in the first place?
I still have to long tube that goes through the trunk and comes back out under the car, that should be enough for venting or not??

edit: To add, i have a supply line and return line in use from the vapor separator.

 

[Cojohnso1]

When i replaced my fuel pickup on my '69 Coronet i blocked off the short vent tube.
Why does it have 2 vent tubes in the first place?
I still have to long tube that goes through the trunk and comes back out under the car, that should be enough for venting or not??

edit: To add, i have a supply line and return line in use from the vapor separator.

Why? We're you too seeing leaking? And I'm assuming no ill effect of just blocking off the shorty?

 

[Wietse]

Why? We're you too seeing leaking? And I'm assuming no ill effect of just blocking off the shorty?

No leaks, but when i installed the new pick up and got the tank back in place i wondered why that vent was there.
As the long vent goes up high and through the trunk i was in the understanding it is enough for safely venting the tank and the short hose was not needed.
I could see the potential of fuel leaking from the short hose when slamming the brakes so there fore i just blocked it.
No effect at all indeed, driven it like that for a long time already.

 

[Fran Blacker]

No leaks, but when i installed the new pick up and got the tank back in place i wondered why that vent was there.
As the long vent goes up high and through the trunk i was in the understanding it is enough for safely venting the tank and the short hose was not needed.
I could see the potential of fuel leaking from the short hose when slamming the brakes so there fore i just blocked it.
No effect at all indeed, driven it like that for a long time already.

Lose gas in the Netherlands your throwing real money!

 

[Wietse]

Lose gas in the Netherlands your throwing real money!

Yep! $6,81 a US gallon.....
Considered to block all vents so nothing will evaporate

 

[kiwigtx]

Why does it have 2 vent tubes in the first place?

One vent tube is at the rear of the tank and the other is at the front....so no matter which way you park the car...facing up or downhill, the tank will always have a chance to vent off the fumes and pressure built up by fuel expansion.

 

[Cojohnso1]

One vent tube is at the rear of the tank and the other is at the front....so no matter which way you park the car...facing up or downhill, the tank will always have a chance to vent off the fumes and pressure built up by fuel expansion.

Mine seems not to be related to stance. It's only at certain fuel level. (Over 3/4) and pressure. And only when motor is off. Again, I open gas cap. It stops immediately. And by the time I get it home. Fuel level dropped and I can't re-create. Has anyone read or have evidence that today's fuels create higher vapor pressures? It could be a combination of sending unit and age of tank? And of course, the harder I try to re-create the less likely to occur. It's like the pipes stop linking when the plummer is in the house? It's not a deal breaker problem. I just haven't been filling it full. But I do keep a closer eye in case it gets worse. But so far? Not. Going on one year and 2500 miles later.

 

[steve340]

I have never read anything about the subject but I feel the modern fuel must give off more vapour than the old fuel, therefore building up more pressure for the vents to cope with.
Given the number of people that have this problem with the B body cars it is hard to imagine that many faulty repro tanks or a suspect OE design.
Surely it must of worked properly when Chrysler built the cars.
If the cars were prone to this venting problem when new it would be a poor design issue.
I would be interested to hear from someone who has owned a car for a long time that has the original fuel tank in it.
From my experience if you drive around with less than a half tank of fuel you would rarely if ever get fuel coming out of the vents.

 

[Wietse]

I think this thinking goes beyond reason a bit here.
The fuel is not being pushed out by pressure due to vaporisation of the fuel, neither will the modern fuel vaporise more or less then the old fuel.
In my reasoning, modern fuel will evaporate less caused by modern dopes in the fuel to prevent this but that's just a quick thought and no proof to support it....

The little vent line should be all the tank needs to relief any excessive vapour and not build up any pressure...unless it is blocked but then you would hear the pressure release when you remove the fuel cap.
Even then, when the fuel tank is full it will pour out of the filler neck first so if that is not the case it means there is still air in the top section of the tank.
How could fuel be pushed up through the vent tube because the vent sits right at the tank top?

 

[steve340]

How could fuel be pushed up through the vent tube because the vent tube sits right at the top of the tank?
Exactly what we are trying to work out. Why do the vents not cope? No one is dreaming it - it happens and it seems it happen to quite a few people.

 

[Cojohnso1]

How could fuel be pushed up through the vent tube because the vent tube sits right at the top of the tank?
Exactly what we are trying to work out. Why do the vents not cope? No one is dreaming it - it happens and it seems it happen to quite a few people.

A dream? Umm. Not my luck. And yes it's not unheard of. If right circumstance it can spill about a pint or two. (If I was to let it go.) But like I said. Its at a high level. And fully warmed up. The warmer outside the more likely. Just strange.