Originally Posted by ExcursionDiesel
Just looked at the fancy cap. It fits the ID. Probably the same. I like the version with a magnet to hold it when it's off. Saw it on the Ram EcoDiesel forum.
Interesting. I like the design, but I would have chosen to not
have the magnet. Our fuel door is genuine, extra-virgin plastic and I wouldn't want to stick the cap on the painted body. I suppose I could tape some ferromagnetic metal to the inside of the fuel door to hang it.
Furthermore, based on the pictures I saw I wasn't certain how securely the magnet was attached to the aluminum cap; it seemed like something that could potentially be jarred loose by a few drops on concrete, then subsequently fall off in the filler neck and have to be fished out.
I like your solution of a DWV cap. Do you know if that material has a reasonable thermal expansion coefficient? You mentioned it was a tight fit. I wouldn't want to try refueling on some subzero day only to find it had turned into a vise-like grip on the filler cap.