Gas puddle from tank vent line

[MYSINBIN]

the cap should be vented. non-vented caps are for emissions vehicles with vapor canisters. mine is marked "vented" "anti surge" and is oem. other thing to check is o-ring sealing the sender.

Sounds like some clarification is needed.

1. Knebel, is your filler behind the rear license plate?

2. rags, are you using your '65 300 as a reference? If so, where is the filler?

3. If the tank and cap are vented, and the filler is behind the license plate, fuel will slosh rearward on acceleration and spill out through the vented cap.

4. My FSM is at the shop, but it specifically states that the vent lines must be kept open/clear. Otherwise the fuel tank will collapse due to airlock as it drains. This reasoning pretty much dictates that the cap is not vented.

5. All of my '67 Newports have non vented caps. None of them are "emissions cars with vapor canisters". None of them leak fuel anywhere unless something is compromised. No matter what fill up/top off technique is used.

Hope the input helps.

John

 

[commando1]

Before self-serv, the standard phrase was, Stop at the first click, don't round it off.

 

[Big_John]

Before self-serv, the standard phrase was, Stop at the first click, don't round it off.

Actually... It was ...shuffle through the wallet.... "Give me... ummm.... $6 of premium".

 

[rags]

rags, are you using your '65 300 as a reference? If so, where is the filler?

'65 300 is behind fuel door above plate. '69 is behind plate, but oe cap is long gone so can't vouch for it. cap currently on '69 has "caution open slowly"! have to admit, i'm with the $6 club above.

 

[commando1]

"caution open slowly"

That's an unvented cap, then.

 

[rags]

That means sealed tank. Unvented.

relevant issue is that it's not oe. might have come from anything. was the first under the bench cap that fit.

 

[commando1]

relevant issue is that it's not oe. might have come from anything. was the first under the bench cap that fit.

You see that I reworded it while you were replying...

 

[MYSINBIN]

the cap should be vented. non-vented caps are for emissions vehicles with vapor canisters. mine is marked "vented" "anti surge" and is oem. other thing to check is o-ring sealing the sender.

'65 300 is behind fuel door above plate. '69 is behind plate, but oe cap is long gone so can't vouch for it. cap currently on '69 has "caution open slowly"! have to admit, i'm with the $6 club above.

relevant issue is that it's not oe. might have come from anything. was the first under the bench cap that fit.

Now I need clarification.

John

 

[rags]

Now I need clarification.

John

you asked me an honest and direct question and i gave you the most honest and complete answer that i could. see question 2, post 21. c'1 made a point of fact that i do not disagree with.

 

[commando1]

Summary:
Stop the fill-up at the first click.

 

[Knebel]

Yes, filler on the back behind the license plate. Well, it drives me nuts too, and I dont like that everyone puts that metal filler cap on the trunk instead on the floor next to them. Gotta put a steel wire on it or so that it can hang loose. Man, when I get gas, most of the employees can barely remember the grade of fuel and the amou t of money i am asking. Now adding the "stop at 1st click" might be challanging.

 

[rags]

on my '69 i use the cap to prop the plate open.

 

[fury fan]

Old thread, but...
My 68 Fury never leaks from a vent tube, actually none of mine ever did. So I disagree that it's normal. Modern EFI-era fuels are designed to evaporate more easily, but again, none of mine leaked from vents at fillup.

I would say a vent tube is blocked slightly, the non-vented cap allows pressure to build, and it 'pops' thru the vent tube. And those vent tubes aren't just a fitting, they run thru the tank, usually to opposite end of the tank to prevent slosh from traveling full-length.

Easiest solution is to not fill it up as much, but further investigation/repair is a more solid/complete response to teh situation.

 

[OneEyed]

My car always seems to spit fuel back at me while filling up. Usually around 10 or 12 gallons it does this, then I have to just barely pull the trigger and let it trickle in til I can't stand it any longer and give up around 16 gallons...and now the damn thing isnt even reading correct on the gauge again. Reads about 1/4 when it should say 1/2. New sending unit was installed earlier this year too. But I dont feel like fighting that crap again, maybe next spring...

 

[73Coupe]

I have a tank collapsing issue. Vented cap (as original) and behind the plate. The vented cap is to let fumes out, but it doesn't let anything in. When it gets down to half tank, under constant driving, the tank collapses a little upwards, and I get a loud bangin' sound when going around corners or accelerating (as the weight of fuel sloshing affects the areas collapsing). So I figure it must be a vent line blocked somewhere? I got 4 lines coming out the tank. I need a new tank (rust), and sender (gauge not working well), which is on the to-do list, so will address it then. Vans Auto will be my source.
The only time I had fuel coming out the cap was when parked facing uphill on a hot day. The fumes expanded to the point the gas leaked past the gasket on the cap and dribbled out.

 

[fury fan]

Yes, a tank collapsing like that is due to pressure not being able to equalize, and in your case I would agree due to blocked vents.

 

[Big_John]

I have a tank collapsing issue. Vented cap (as original) and behind the plate. The vented cap is to let fumes out, but it doesn't let anything in. When it gets down to half tank, under constant driving, the tank collapses a little upwards, and I get a loud bangin' sound when going around corners or accelerating (as the weight of fuel sloshing affects the areas collapsing). So I figure it must be a vent line blocked somewhere? I got 4 lines coming out the tank. I need a new tank (rust), and sender (gauge not working well), which is on the to-do list, so will address it then. Vans Auto will be my source.
The only time I had fuel coming out the cap was when parked facing uphill on a hot day. The fumes expanded to the point the gas leaked past the gasket on the cap and dribbled out.

If your car is a 73, per your screen name, you won't have a vented cap like earlier cars. You will have a vapor separator and a charcoal canister under the hood with vent and purge lines to the carb. Everything has to work right.

This is all covered in your FSM. If you don't have a service manual, download a 73 Dodge Chassis Manual here: MyMopar - Mopar Forums & Information - Service Manuals

If you have a Plymouth or Chrysler, this will get you close enough until you find a FSM elsewhere.