1936 Dodge Fuel Tank leak

[Guest Atari1977]

So today while I was filling up the Dodge the pump automatically came to a stop. I pushed it again because I thought it needed more. Then I saw fuel leaking from the top of the tank and dripping off the bottom. So I stopped filling it up and the leak stopped shortly after. It hasn't done it since. The tank was recently dropped in order to look at the fuel gauge sender(which we don't think is resisted right for the tank), so is it likely a gasket is loose or did I overfill it? This is a newer plastic tank if that makes any difference.

[1936 D2]

I don't know much about plastic tanks myself, but I would think that if you get the tank to a point where it is clean and dry on the outside (be sure to remove the cap so expansion pressure doesn't keep the leak going) then jostle the car a bit so the fuel just starts to leak. Follow the fuel leak back to the source.

Most likely will be a gasket area but you could have a small hole from a scratch in the plastic near the mounting straps or such. Either way, this fresh leak should help direct you back to the source.

Also, do the plastic tanks have some type of pressure release valve on the top of them to prevent an over pressure situation from expanding fuel? A check with the manufacturer of the tank will answer this question.

Edited July 17, 2013 by 1936 D2 (see edit history)

[Guest Atari1977]

I doubt the fuel tank has been punctured, the leak seemed to be coming from the top and it hasn't happened since I filled it up. I believe it's this model 1935 1936 Dodge Plymouth Mopar Street Rod Poly Gas Tank | eBay , it was installed years ago though.

[1936 D2]

True. Since this poly tank has a venting feature and there is none on the original style tank, I suspect your "leak" is coming from this vent.

The original tanks use a vented cap (which is probably illegal now) to vent fumes into the atmosphere and air into the tank as the fuel is extracted. Newer cars have a vapor canister that recycle these vapors back to the tanks from the engine area. This is what the vent is for on your poly tank. Of course, since there is no canister system on the original cars, your tank vent connection is open. That is the most likely place for your "leak".

I would check about getting a rubber fuel line piece and extend the tank's vent opening as high as you can. Finish this vent line in a "J" shape with the opening pointing down. This will help prevent deep water from entering the tank vent. Then it will match the idea of the vented gas cap and also prevent liquid fuel from leaking out of the tank. Also, maybe stop your fill at the first click of the pump.

Edited July 17, 2013 by 1936 D2 (see edit history)

[Guest Atari1977]

I guess it was coincidence I went to gas station who's pump once stopped at a gallon when the tank was near empty. Thanks for the advice!