Leaking gas on side of car..help.

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66DartSedan

66DartSedan

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If you zoom in youll see I'm noticing what looks like remnants of gas leaking from the gas tank. I was searching and I've found that mopars didnt use vented gas caps, HOWEVER, the prior owner installed a unvented gas tank (CR11A 1966 DODGE DART GAS TANK,) and a SENDING UNIT -- 5/16", SINGLE LINE. So does that mean if I don't currently have a vented gas cap, it would cause spillage? Or Do I need a vented cap?

20171202_144454 (1).jpg
 
Actually, no and no.

There is nothing such as an unvented gas tank for a '66 Dart. The CR11A is a direct replacement for the original tank, which is vented by means of a 3/16" steel line that comes out the top of the tank and runs up the left-front corner of the trunk compartment, makes a sharp U-turn and heads back down, through the trunk floorpan, and the open end is not far from the tailpipe. You can see a portion of the vent line in the first pic (click to enlarge) on this page (he calls it the "vapor line").

A vented gas cap is not required nor helpful on a car like yours, which was not designed to use a vented cap, and there isn't one that will readily fit. If you cram or adapt one on anyhow, you will worsen the gas-down-the-side-of-the-car problem, not improve it.

Make sure the face of your filler neck (where the gas cap seals) is smooth and not dented, scarred, or otherwise defective. Get one of the good-sealing caps from @damraider on here, make sure your fuel tank vent is properly installed, properly routed, and not blocked, and you'll be good to go.
 
72Dart6pack said:
Yes & Yes.
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Ah damn. Okay I was racking my brain and the forums. Im new to all this can you walk me thru exactly what is happening?
slantsixdan said:
Actually, no and no.

There is nothing such as an unvented gas tank for a '66 Dart. The CR11A is a direct replacement for the original tank, which is vented by means of a 3/16" steel line that comes out the top of the tank and runs up the left-front corner of the trunk compartment, makes a sharp U-turn and heads back down, through the trunk floorpan, and the open end is not far from the tailpipe. You can see a portion of the vent line in the first pic (click to enlarge) on this page (he calls it the "vapor line").

A vented gas cap is not required nor helpful on a car like yours, which was not designed to use a vented cap, and there isn't one that will readily fit. If you cram or adapt one on anyhow, you will worsen the gas-down-the-side-of-the-car problem, not improve it.

Make sure the face of your filler neck (where the gas cap seals) is smooth and not dented, scarred, or otherwise defective. Get one of the good-sealing caps from @damraider on here, make sure your fuel tank vent is properly installed, properly routed, and not blocked, and you'll be good to go.
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Now I trust you, but Im confused. I called Classic Car auto part where he bought the tank asking if it was vented and he said "I'm looking at the photos and I don't see one" Okay well I just ordered a gas cap from @damraider.
 
When exactly is it leaking?

Underground fuel tanks stay cool.

Like may other elements, gas expands at it warms up.

So if you fill your tank at a gas station all the way & let the car sit in a warmer atmosphere, the fuel in your tank will warm up, expand & find a way out.
 
Every single picture I find of the CR11A tank shows no vent in the tank at all. I know on my 65 Valiant, the vent came out of the filler neck toward the top and ran back along the filler neck through the filler neck grommet and out the bottom of the trunk.
 
66DartSedan said:
Now I trust you, but Im confused. I called Classic Car auto part where he bought the tank asking if it was vented and he said "I'm looking at the photos and I don't see one"
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Your tank is vented, just not by means of any fitting or port or tube on the tank itself. the "tank" end of the vent tube I described previously is actually near the outboard end of the filler neck. Open the trunk and see for yourself. It's up there rather than down at the tank because up there at the top of the filler neck it doesn't usually see liquid fuel -- unless you overfill the tank when it's cool out, then it gets warm out, the gasoline expands, and pushes its way out the vent tube. Make sure that vent tube is present, not crimped or dented shut anywhere along its length, not clogged with debris. That plus Damraider's cap will solve the problem.
 
slantsixdan said:
Your tank is vented, just not by means of any fitting or port or tube on the tank itself. the "tank" end of the vent tube I described previously is actually near the outboard end of the filler neck. Open the trunk and see for yourself. It's up there rather than down at the tank because up there at the top of the filler neck it doesn't usually see liquid fuel -- unless you overfill the tank when it's cool out, then it gets warm out, the gasoline expands, and pushes its way out the vent tube. Make sure that vent tube is present, not crimped or dented shut anywhere along its length, not clogged with debris. That plus Damraider's cap will solve the problem.
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Okay is that what is thing is sticking out? The vent?

Screen Shot 2017-12-23 at 12.32.23 AM.png
 
Yes sir! That's it. It should have a small line attached there with a short section of hose. The line will turn back and go along the filler neck like I described in post #6.
 
Yep, that's it, and it must be routed as described in post № 3. It has to go way up high to the upper-front-left corner of the trunk compartment and then turn back down and go out the trunk floor. That high loop is necessary to prevent liquid fuel sloshing out the vent.
 
slantsixdan said:
Yep, that's it, and it must be routed as described in post № 3. It has to go way up high to the upper-front-left corner of the trunk compartment and then turn back down and go out the trunk floor. That high loop is necessary to prevent liquid fuel sloshing out the vent.
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SO, this is the routing youre talking about.

filler tube - in.jpg
 
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