Fuel leak

[code3z]

Here's the deal, I have a fuel leak coming from the gas cap area. If the tank is more than 1/2 full and I make a sharp left turn, gas will leak out from the cap area and down the side of the car (YIKES). Not a good thing for the paint. Ive replaced the gas cap, gas flap and tighten all the screws. Not sure what the problem is. Anyone got have an idea about what's going on? Is there a NOS fuel filler neck replacement part?

[Dude76]

sounds like the filler hose is loose or cracked.(dry rotted maybe). put on some safty goggles and inspect it if you see nothing get a towel make sure there are no sparks in the area and have a buddy shake the car and see where gas is coming from.May also bee a loose vent tube but that wouldnt leak at the filler cap.

[AZ-240z]

Check the most obvious, which you probably already have. Inside the gas cap, there should be a rubber sealing ring which may be torn. The gas cap, itself, mates to a flange ring (not sure what you would call it). This flange ring is mounted to the body with a rubber protector flap between it and the body with three screws. It, too, may be rotted and not providing a proper seal to the filler hose. If both of these are sealing properly, there is not way for gas to get outside of the cap and on the paint.

Let us know what you find, and good luck.

Dan

[beandip]

I cannot tell by your picture what year your Z is . However in any case . The large filler hose attaches to the metal end that has the cap. I know on my '73 you access the upper clamp via the inside of the car. You remove the plastic panel on the passenger side in the rear corner of the hatch area. On a later car access is up in the back of the wheel well. On both models , there is a small panel of metal held in place with three sheet metal screws right in back of the right rear wheel. When this triangular piece is removed you will be able to see all of the filler neck. The early cars have the rubber filler hose that goes all the way from the tank to the underside of where the cap section is located . the newer years have metal extension that extends down from the cap area in the fender well under the car. Hope this helps. Be careful with these large hoses because they are not cheep. All the best, Gary

[beandip]

Otherwise see if you can tighten the gas cap so it will seal tight. They can be made to seal tightly by SLIGHTLY bending the ears that attach the cap to the filler neck. Gary

Edited February 3, 2009 by beandip

[code3z]

Thanks for your help. My car is a 72. The cap, rubber ring and flap are all new. Ill have to check the filler neck for cracks. Maybe i should just replace the entire setup since it is 37 years old.

[rtaylor]

Hard to do with it still in the car. I found a small crack in mine but on the back side adjacent to the tank Only found it by pulling it out. Also found that the tube coming out of it was cracked, so while I was at it I replaced all of the evaporative tank hoses, as they were 36 years old too...In order to check those you will need to pull the right rear interior panel as Gary said. Expensive job. I think I paid close to $200 for the filler hose.

[biddljj]

Is the gas tank wet with gas on the passenger side ? If yes.... The rubber

tube used to fill the tank is leaking.

If the gas is on the outside of the body it's probably a gas cap or maybe loose fitting. The part that the gas cap screws into is just a plate that sandwiches the top of the rubber filler tube against the body. If that's loose gas could sneak by...

Is the gas cap tight when you screw it on ?

Jay

Not just a Z - zdisease

[code3z]

All fittings are tight and no noticable cracks. No fuel on the tank just in the gas filler area. Mmmm, kinda stumped. Next step is to replace all of the gas lines since it is almost 37 years old. Thanks to all who wrote.

[Mike B]

You may want to refer to this thread regarding replacing the various gas hoses with OEM or not.

http://www.classiczcars.com/forums/showthread.php?t=25857&highlight=gas+hoses

-Mike

[EScanlon]

All fittings are tight and no noticable cracks. No fuel on the tank just in the gas filler area. ....

Could it be that the sequence of assembly is off?

The rubber flap/apron goes over the filler neck flange and mounts BELOW the filler neck flange, next the filler neck flange which is then topped off by the filler cap mounting ring. This is from the metal "cup" out.

If you mount the flap on top of the filler neck flange the mounting ring cannot exert pressure evenly over the whole flange and you get a leak.

FWIW

E

[racebird1]

Your problem sounds like it is in the cap area and not the mount of the neck on down because all hose connections problems would cause the fuel leak to run down inside the car behind the trim pannel and the gas smell would drive you nuts. Your problem is most likely from someone leaning hard on the fuel nozzle when filling up and thus slightly bending down the top lip of the filler neck preventing a good seal with the cap and gasket. To repair this you would probably have to remove the filler neck and if possible carefully bend the top of the filler neck back into it's proper position.