C2 Gas Fumes

[Joe T.]

I have a 1966 427 425 HP. My garage has the smell of gas fumes. The gas cap is an original vented cap. I am using aviation fuel. They seem to have increased with the use of aviation fuel. Can not see any leaks underneath. The smell is coming from the back. Any thoughts and/or recommendations?

[Harry S.]

Re: C2 Gas Fumes

Had the same problem. Added a second gasket on the gas cap, problem solved.

[Larry M.]

Re: C2 Gas Fumes

You may have a bad gasket or gasket leak between the tank and the filler neck. Try to tighten (gently tighten) the 10 or so small head bolts, and if that does not work replace the gasket. Also try and keep the tank level about 2/3 full or less. Don't fill up to the very top (20 gallons).

Larry

[Rich G.]

Re: C2 Gas Fumes

Check for leaking fuel sender, too. I had that on my 66.

Rich

[Joe L.]

Re: C2 Gas Fumes

I have a 1966 427 425 HP. My garage has the smell of gas fumes. The gas cap is an original vented cap. I am using aviation fuel. They seem to have increased with the use of aviation fuel. Can not see any leaks underneath. The smell is coming from the back. Any thoughts and/or recommendations?

Joe------


Use a gas cap with a rubber gasket. Save the one with the cellulosic (paper) gasket for judging only. The 1969 gas cap (also SERVICE for 1963-68) has a rubber gasket. It's GM-discontinued but available as manufactured by Stant. Stant #10853.

Also, the gasket between the fuel filler and tank is very failure-prone. It is a cork gasket. I recommend making a new gasket out of a sheet of buna-N material. This will be a forever gasket. When replacing the gasket you also need to straighten the flange of the filler neck. It will be distorted at each of the screw holes. Simply use a small hammer and wood block to straighten it much as one does for oil pans. Also, you need to replace the special screws with new ones with the same rubber seals. Re-using the screws sets you up for continued leaks, liquid or vapor.

[Joe T.]

Re: C2 Gas Fumes

Thanks to all of you I found my problem. The sending unit was replaced last year. It started to have a very small infrequent drip. I removed the spare tire and support then was able to tighten it from the bottom. I also replaced the gas cap gasket.

[Timothy B.]

Re: C2 Gas Fumes

Joe,

Are you saying the locking ring on the sender was not completely turned to it's stop?

If that's the case I would recommend not using the shop that replaced the sender as it's mounted on the tank bottom which could be disaster if the locking ring failed because of not being turned to it's stop. IMO, it's something that does not get installed wrong.

[Dan B.]

Re: C2 Gas Fumes

Joe,

Are you saying the locking ring on the sender was not completely turned to it's stop?

If that's the case I would recommend not using the shop that replaced the sender as it's mounted on the tank bottom which could be disaster if the locking ring failed because of not being turned to it's stop. IMO, it's something that does not get installed wrong.

There is no excuse for that (agree with Tim 100%) in fact, the newer vehicles also have locking rings for the fuel pump assemblies (which incorporate the sending units) so even a new car mechanic should be able to do it properly.