Hi spiregroup. Welcome to the forum. It is certain you have a leak, but that is to be expected. Every AC system leaks a tiny amount of refrigerant. At 16 years old, it would be typical to have had your system recharged twice already.
You'll have to find a state where it is legal to sell the one pound cans of refrigerant. Check the label under the hood, but most likely your system uses R-134. If the compressor still runs, the system is not totally empty, and if it worked last year, it will probably only need one can. If the compressor does not turn on, the system pressure is too low. That would suggest a major leak. You might be able to find a can of refrigerant with dye added to show the location of the leak, otherwise you'll have to use an electronic leak detector which you might be able to rent or borrow from a parts store.
If you add a can, always keep it upright so only vapor boils off and enters the system. Liquid will lock up the compressor. If it takes more than two minutes and the can still has refrigerant in it, place it in a pot of hot water. That will empty the can in 15 - 20 seconds.
It would be wise to wear a face shield, or at the very least, safety glasses. Refrigerant will freeze eyeballs and cause frost bite. Be sure to replace the cap on the nipple. Valves leak. They are only meant to hold the refrigerant in until the cap with the o-ring seal can be installed.
Sunday, May 30th, 2010 AT 12:28 PM