Gas tube, gas spits out vent

[55 cadi]

Hello all,

I was filling my gas tank, it was about half way filled on a 20 gal tank, and gas started spitting out the vent tube that is near the top opening where you fill gas, that is inside the tube.
55 Cadillac, sedan
What would cause that?
Stumped.

Also, it's a fairly new tank, new sending unit and new tubes attatched.
One more thing is I have a heavy gas smell whenever the tank is filled half way, if it's less then I don't smell gas in garage, no visible leaks

Thanks
Jason

[Jeff Rosansky CLC #28373]

Have you actually had a full 20 gallons in it? You say new tank. Is it repaired, NOS or a reproduction tank. Any chance it has baffles in it?
Jeff

[55 cadi]

Reproduction, new, exactly the same tank
No baffles
Only half to 3/4 tank filled

[J. Gomez]

Jason,

The vent tube on the side of the main filler pipe connects to the fuel tank vent outlet. If yours is leaking at the top were the side vent tube enters the filler pipe you may have a weak welding seam around the area and/or possible the leak is at the bottom of the vent tube where it is welded to the main filler pipe before it bends towards the fuel tank. 

There is always going to be some fuel smell around the area as the fuel system is not a close setup, but a heavy smell may indicate there could be a hole venting fumes somewhere in the tube(s).

Good luck..!

[55 cadi]

Thanks Jose, I will check,

But it isn't leaking out the bottom, while I am filling tank with gas, gas will spit out of the top of vent tube hitting me with gas while I am pumping gas in.

What would make the gas go up the vent tube and come out the top of it.

And the gas nozzle is past the vent tube while I'm pumping gas.

Jason

[Mike Josephic CLC #3877]

Jason:

The vent tube arrangement on these tanks is not the greatest design.
The tubing is a very small diameter allowing pressure to build up in the
tank if you fill it too fast, especially when you go past half way.

Take it S-L-O-W when you fill up and that will help.  Also, avoid
filling it to the very top and squeezing in that extra quart or two.
I learned this lesson working at a gas station in the 60's.

The '55 Eldorado had a severe issue with this problem due to the filler
neck being lower (fill neck was on the middle of the quarter panel).  This
required a mid year workaround to correct.  Gas on these would spill out
if you made a sharp right turn and the tank was over half full.  Mine does
this as it was an early model year car.

Although, I've not heard this being as much a problem on the standard
55's I'm not surprised.

Mike

[55 cadi]

Thanks for input, it hasn't done that before, so pump may have been fast.
I just didn't know what would cause the pulsating action of the gas coming out of the vent tube, spit out, stop, spit out, stop , spit out, stop and so on.

Thanks again
Jason