[Darth Menace]

Hey I just filled up and when I stopped I saw a dribble trail coming from the car. I looked underneath and saw this. Is my tank leaking or is there an overflow valve/vent or something?

[rohrt]

I found If I over fill my car It was leaking from the rubber O-ring on the sending unit.

Do you have the factory old lines connected to the gas sender? I would just jake it up and take a look.

[70pontiaction]

I've had plenty of Pontiacs do this when the tank is totally full. Some only leak a couple drops when you shut them off. Others dribble a puddle as the exhaust heats up the fuel in the tank.

I know that the 1970s have a vent line with a rubber hose in that corner of the tank - not sure if they used the vent on the 1968-69s. But you still have the rubber fuel line and/or return line that will probably be rotten if they're more than a couple years old.

Grab some good, ethanol-resistant rubber fuel line and half a dozen new clamps and jack it up (or get it on a lift, if possible). It should be an easy fix.

Good luck!

[Simple Man]

My 69 had a vent on the corner of the tank, that had a fuel line on it, that went up into the frame. The hose was rotted, and leaked.

[Darth Menace]

Thanks for all the replies guys. I have been putting a lot of my spare time into the en suite so I didn't get a chance to read these or take a look at the car. I will take a peek tomorrow and report back. Hopefully it is just a rotted rubber line like you mentioned

[nogto]

It may be a little late to help you but I found another potential source of a leak like yours. I was reading about fuel tank leaks on the forum trying to figure out the source of a strong gas smell in my garage. It seems that the smell is strongest after I top off the tank and park it in the garage. I never did find any gas dripping on the floor however. At first I though it was just one of those old car smells you have to expect, although the tank and all the lines are new.

I saw this post and then crawled under the tank to check for leaking hoses or a fuel sender gasket. It turned out that there is a small leak where the filler neck is soldered to the tank. It leaked very slowly and collected on top of the seam where the tank is crimped together. It was never enough to show up on the floor but it did collect toward the front corner of the tank rather than below the neck because of the angle of the tank seam. I removed 5 gallons from the tank and that stopped the leak and the smell. Now I just have to remove the rest of the gas and take the the tank out to have it resoldered.

[kyle_blake]

the vent rubber line on that side of the tank has a small sponge type material inside it. check out that part. the 69 gto service manual shows it.. i have it saved somewhere. will hunt it down.

all I could find is gas tank pics from when I dropped the tank. you can see the hose on the side in question.

[Darth Menace]

So mine doesn't smell like gas fumes or anything. I will replace that vent line and be done with it. Just glad it isn't the fuel tank itself. That would suck royally

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