1964 Cadillac fuel smell

[Rob Leonard]

My AC equipped '64 is outgassing fuel odor and I can't find it's origin.

The smell is constant, but more pronounced when the tank is more full. There is no sign of a fuel leak anywhere in the fuel system. I've spent time underneath the car, and the smell is definitely coming from around the front of the tank. At the back of the tank I've determined that it's not coming from the filler pipe or the filler neck. I replaced the rubber lines from the front of the tank a couple of years ago with fuel injector hose and they look brand new with no signs of seepage at their connections. There is no sign of a leak from the fuel tank vent pipe or its rubber connection-to-the-tank hose.

I can think of only two possibilities:
1) I believe that there is some kind of gasket where the fuel lines and sending unit enter the tank on its top. If it has failed, then that could explain the constant gasoline smell.
2) What keeps the fuel vent pipe from emitting gas? If there is some type of vapor barrier in it that has failed, then that could be the source of the odor.

Any informed advise is much appreciated.
Thanks, Rob Leonard 310-753-8079

[kevinanderson]

Had this issue. Mine was a rust hole on top of the tank. More gas in tank. Stronger the odor. 

[dadscad]

I had an issue like this on my 63 many years ago. I found the cork gasket on the fuel sending unit to be leaking. HTH

[Rob Leonard]

I'm guessing that it is the cork gasket on the fuel sending unit because my car has always lived in CA and is completely rust free.
Is this a gasket that I can make out of rubberized gasket material - that I already have in my garage - or is it something that I should order from a parts supplier?
If the latter, I'd appreciate any leads on a parts supplier that would have this gasket.
Thanks, Rob

[Daryl Chesterman]

Rob, unless you have some gasket material that is compatible with ethanol gas, I would suggest buying one.  It is too much work to have to replace the gasket again if you don't know about the composition of the gasket material.  I just did a quick search and found that Caddy Daddy has a gasket for $25.  There may be other sources that are less expensive.

     https://www.caddydaddy.com/shop-parts/1956-1957-1958-1959-1960-1961-1962-1963-1964-1965-1966-1967-1968-1969-1970-cadillac-gas-tank-sending-unit-gasket-reproduction-free-shipping-in-the-usa.html

Daryl Chesterman

[Rob Leonard]

Thanks. I went ahead and ordered the gasket from Caddy Daddy. Like you said, get it done right the first time.
Any tips on how to avoid problems with the installation?
I plan to run the car low on gas and then remove the tank to replace the gasket. The fuel delivery system is fine and the gas gage works fine. I plan to replace the tank-to-vent-pipe and fuel tank filler neck hoses with NBR fuel hose material. Any think else I should replace while I have it all apart? Rob

[dadscad]

I wish I had been more observant when I did my car's gasket, but I wasn't.  Pay attention to the location of the felt pads under the tank straps and the pads located on top of the tank so you can get them back in place for the assembly. HTH

[russ austin]

Replace the short run of fuel hose on the vent tube. It gets old and dry rots. Gas seeps out and evaporates before it drips onto the floor.