There was a thread started on this about a month ago. Some folks mentioned they would get a check engine light set when using a locking gas cap...others said it was fine.
It was also mentioned that if your RV is stored, the new trick for gas thieves was that they slide a container under the tank, and puncture a hole into the bottom of the gas tank and drain it. A locking gas cap does not really do much these days to anyone who wants your gas.
I ended up buying a white bezel that has a locking door flap. I removed the black bezel that holds the gas filler neck, installed a piece of angle iron behind the opening, bought a filler neck hold down (used on F450 flatbed arrangements), then installed the white bezel with a lockable door flap against the outside wall.
As a bonus, I found a kink in the rubber fuel line that connects the metal fuel filler tube to the gas tank. The rubber tube was too long, so it had a bad pinch in it at the gas tank neck. I cut off about an inch and a half from the rubber fuel line, and reattached. I now know why I could only fill the tank slowly, and it would only take 3/4 of a tank when I filled it; the kink would hold gas back to the filler neck, shutting off the pump.
The locking door gives a bit of security (as much as a locking gas cap), and sits flush against the body, eliminating the black bezel, a cleaner look IMO.
The camper sits in my driveway, so I don't worry much about the gas tank getting pierced to steal its gas.
First pic is the door I installed, and second pic is what I eliminated.
Could work either way, but I mounted it so the lock is at the top, hinge at bottom, so the door opens down.
Also, not all holes from the black stock bezel line up to the new white door, but the old holes are hidden with the new white locking door. Yep, you will drill new holes, but no big deal.
I'll snap a pic of mine installed and post it here.
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