Question, did the valve have a black plastic cap on it?
If it didn't then get one as this is actually the primary seal!
Yes, I do have the black plastic caps on both valves. But they are not full screwed on tight, as one Vx tech guy said if you tighten it fully the middle part of the cap will touch the valve and the gas will escape.
So I had it like 75% tight.
Recently I changed the rocker cover gaskets, As a gengeral check I do go over all the nuts, bolts to make sure they are up to the torque values. Part of this check I might have also over tighten (by hand) the aircon valve black caps.
Is there a torque value for the caps?