QuestionDick, I just bought a 1966 Mustang 6 cylinder. I am noticing a gas smell in my garage, but can't locate a leak. When the gas level is low (about 1/8 of a tank) the smell is gone (or mostly?) When I put 5 or so gallons in this weekend, the smell came back. I'm a novice, so don't know where to start. Thanks.
AnswerAssuming it has not been done recently, you should start out by replacing all the rubber tubing in the fuel lines - the old tubing isn't able to stand up to the new oxygenated fuels now being sold, so the old stuff is most likely cracked and seeping. Be sure to check the tubing back at the tank, also, in addition to any from the frame to the fuel pump inlet, and from the fuel pump to the carburetor. Make sure the tubing you buy for it is marked SAE 30R7 or better - 30R9 is better, but much more expensive, and not really required for your car.
While you are working under the back of the car, try to get a look at the top of the tank where the fuel gauge sender is installed- often there is a bad "O" ring seal there and that will make it leak when the gas level is high enough to splash up on the seal. The O rings are cheap, but you will probably have to lower the tank to get at it, unless there is an access hole in the trunk floor in the right place. Some of these cars had the hole, some didn't.
Don't ignore this, - gas vapor can make a big boom when you hit the starter!
Dick
