Yes, I had the connector to my A/C radiator come lose and completely discharge the system. I have also seen the refill valve core get a bit loose and cause a slow leak. I went to the auto parts store and bought a valve core tool and retighted the core and stopped the leak
I've been trying to figure out my air conditioning and what the problem
> might be. I'd previously added a can of R134A which brought the level up
> to the high end of the acceptable fill range of the gauge. This is the
> reading from the 'low side' of the system schrader port. At the moment,
> what pressure that reading corresponds to escapes me as the gauge is
> currently not within my reach. A week later, the pressure was down to
> the level of the gauge that indicates that more R134A is required. Then
> I noticed something that I never saw before all this but I believe did
> exist for sometime. The 'high side' schrader valve was loose enough to
> rotate in either direction, by hand, clockwise, or counterclockwise.
> Saturn did my retrofit four years ago to the R134A. Can these valves
> work loose somehow? I tried tightening it by hand so far and now am
> wondering what the best advice would be at this point. It worked OK
> going into this last winter and then seemed to peter out. Any
> suggestions or advice will be appreciated. I currently do not have a
> 'high side' gauge. Thanks.
>