I don't know, at least not yet. I could not get eyes on the problem while the system was pressurized. There was no clearance for inspection. So I just removed the whole fitting and capped the stub. And when I removed the fixture, there was teflon paste residue on the threads.
But I hung onto the fitting. I am now trying to figure out a way to pressurize it with my compressor, so that I can see exactly where the air is escaping. I do not see any visible damage.
The weirdest part of this is that I am sure there was no leak during our last big trip, in November. So what could have caused a leak to develop? The bbq fixture was not subject to any stress -- we never used it, and it was tucked up under a frame member.
Wild guess: this is some sort of corrosion?
If I am ever able to isolate the problem, I will post the info.
