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There should be a plastic sealing washer around the black tube. Yes, installed dry.
I had to put the gas resistant Teflon tape on the one I did, it was yellow color not the white, hope this helps.
On the ones I have seen, the seal is a hard white plastic (teflon?) washer in the fitting. Like a crush washer. Since it is not NPT threaded, teflon tape is not likely to work well.I would take it to a friendly auto parts place and se if they have a crush washer that might fit. Of course finding a friendly auto parts place is nearly impossible.
Check, but I think it's a 14 mm ID, 18 mm OD washer. One of these might work:https://tinyurl.com/2n7m3mctRich