I recently tried to recharge my 1994 Saturn SW2 air conditioning. The system took the charge fine, nice cool air again. Yea! On disconnecting the adapter, I heard the sound of escaping gas. I was able to place my thumb over the port and block the leak, tried reattaching adapter and removing several times, but the valve will not fully seal. Placing the cap back on the port with a small piece of plastic food wrap (hi tech) stopped the sound, but obviously not the leak entirely. A couple of weeks and the a/c is back to blowing hot air.
Is there any way to encourage the valve to seal? Should I try the variety of refrigerant that seals leaks? Is there a better choice for blocking the leak than food wrap? If it comes to it, replacing the low pressure line, is that something a person who knows how to use a wrench but not much more can do?