is my air con leaking

[muso58]

This might sound elementary but I know nothing about air con, I have just bought my 944 it was sitting for a year before that with a u/s clutch . my q is when i depress the valve on the air con line it releases pressure, does this mean the system is airtight.as i need it recharged and dont want to waste a refill if it has a leak

[Scott R]

You can have a charge in the system, but not have enough. The fact that you still have something in there is a good thing. The system is sealed and that is good. An exposed system gets crud inside. Get the clutch replaced (this can be done on the car) and get the charge updated.