And out of idle curiosity, I removed the locking gas cap I'm using now to see just how they vented it. If you look below, you'll see a rubber ring seal and if you look carefully you can see a metal piece (ring, actually) inside and below that seal. As it turns out, vapors can go past that ring to the outside in either direction (they seep out on the back side of the rubber ring where a gap exists between that ring and the body of the cap, but the actual filler neck will be sealed against wind, rain, snow, whatever. So, they sort of used the same scheme as GM, but in this case there is no bi-directional valve like the one GM used.
And I should add my wife is fairly horrified to see me sucking and blowing on gas caps here so it may be a while before I get a kiss. But you guys don't care about that, do you?
~ Jon 1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
