Noticed this for a few months. If I fill the tank full I get a gas smell.

A. 2AzFe SULEV A/T 285,000 miles
B. Smell goes away below 3/4 tank
C. No engine code thrown
D. No hiss when releasing gas cap even if silicone grease is applied to gasket

Is it more like coming from the filler neck or the top of the gas tank or someplace else?

Thanks,
John

 

Very possible that there is a crack in the tank in the upper area of it.
I had a Lincoln MKVIII and what you describe is exactly what was happening with this car and I ended up replacing the entire gas tank.
So, fill the tank and crawl under there and look and feel for wet/damp areas. Sniff around as well.

 

It's possible a pipe going from the gas tank to the filler nozzle area is broken or rusted out. The fuel tank EVAP system is located under the car in the area of the gas tank. It has a plastic container that stores the gasoline vapors that can crack. The system has small rubber hoses that can crack. If you can get under the car you can inspect this area.

Normally if an air leak the cars diagnostic system would pick it up when it does a self test. Maybe an actual liquid fuel leak. You can remove the rear lower seat to find a metal plate to access the top of the gas tank and fuel pump area to check for signs of gas.