Gas fumes

I have a few (too many) old cars. They are occasional drivers but there seems to be a lot of raw gas fumes about the car. It’s not a leak at the engine. I think it’s coming from the vented gas cap. I hear that modern gas is more aromatic and worse for the environment. Is there a way of retrofitting my old cars to use a charcoal canister and a sealed cap or something like that to stop the fumes and help the environment?

That would be extremely difficult (nothing’s impossible, of course). Lots of hoses, fittings, connections, design work, etc. Have you check all the rubber hoses and fuel lines from tank to engine? Not uncommon for them to leak on old cars. My '65 Mustang was burned to the ground following the hose bursting in the engine compartment (many years ago). How old are the hoses?

The problem persists with three old cars I have. All are recently rebuilt. I think they always smelled a little but maybe the gas has changed or the seals are not as effective?

Maybe it has something to do with the added ethanol these days. Ethanol has a higher vapor pressure that regular gas, and while they’re supposed to compensate for that it might still result in more, or more odorous, evaporation.