Urgent question - Gas leak?

[Jaybot]

Please help! I just filled up my gas tank of my '63 avanti. Have never had any issues til today and my gas tank is new. After sitting in my driveway for an hour a large puddle of gas appeared. Did I simply unknowingly overfill my tank or this something more serious?

[Gunslinger]

I'm assuming the leak is under the rear of the car. If you overfilled the tank it could be going out the vent and dumping on the ground. If that's the case it could continue until it's empty or you pinch the vent tubing shut with vise-grips. A full tank of gas on a very hot day, along with the car being parked on an incline can allow gas to come out the filler neck, down the side of the car onto the ground.

You need to crawl under the car and pinch off the vent tube if that's the problem. Other than that you might have some problems with how everything was installed with the new gas tank.




Poet...Mystic...Soldier of Fortune. As always...self-absorbed, adversarial, cocky and in general a malcontent.

[Jaybot]

The gas tank is a new, but installed a long time ago. I am on a small incline and it was hot today, so I'll move the car a few feet and see if it stops. If not, then I guess I'll crawl under and check. Thank you!

[rockne10]

May not have overfilled it but, gas from an underground tank is probably about 50 to 60 degrees F. If air temperature warms it up ten or more degrees it's going to expand. Parking with the filler neck downhill (even slightly) just expands the surge. With a freshly installed tank maybe the clamps just need tightened.

[IMJ]

Jay,
My money is on the gas expanding theory. The same thing has happened to me in the past on my Cruiser. It happened on my motorcycle too. On the cycle it was not on an incline, just on black-top in the hot sun. Facing the car downhill might help depending how full the tank is and how hot the day. If you can't get the car in the shade it would be a good reason to go for a short drive and burn off some gas. Better that than softening up the macadam. If it were me I don't think I would pinch off the vent tube, even temporarily. That pressure has to go somewhere.

regards,

Jay (IMJ too)

[raoul5788]

You may have a bad gasket on top of the tank where the sending unit is. I filled my tank once and the gas practically poured out from underneath the sending unit! I had to park going downhill to get the top of the tank level. That stopped the leak and I was able to install a new gasket. The gasket is much thicker than normal ones. You can get some at at FLAPS and cut your own.



Chip
'63 Cruiser
'57 Packard wagon
'61 Lark Regal 4 Dr Wagon

[WCP]

Make sure that the vent line passes into the right rear quarter panel where it should loop upwards to near the top of the side rear window and then down back through the inner panel and then down thru the tank floor support. If the vent is simply taken from tank top down thru the floor, then what you experienced will happen for sure.