A/C leak with slight hiss???

Your 2000 Prizm has a GM/Delco A/C system unlike the Corollas. The Delco A/C compressor is a V-5 variable displacement compressor which are known to leak from the compressor shaft seal after many miles of use. This may or may not be where your leak is, but it is a known area of trouble. When charging, try applying a soapy water mix around suspected areas and look for bubbbles. Or you can add dye to the system when charging to help identify the area of the leak. Also, with a leak that severe, you should see signs of compressor oil at the point of the leak. Another option is to buy, rent, or borrow an electronic refrigerant detector to help find the leak. Check around the compressor shaft seal first. I had to change the compressor in my '99 Prizm because of the bad shaft seal. Got a great deal on ebay on a new Delco compressor. Consider also changing out the accumulator and orifice tube at the same time. You must pull a vacuum of 29 to 30" with a vacuum pump after the system is reassembled, and before adding the refrigerant to remove all moisture and air from the system. Also, if you can't maintain 29 to 30" of vacuum in the repaired system before adding refrigerant, you still have a leak somewhere.

Great advice, thanks! :thumbsup:

And the saga appears to have a happy ending. I took it down to our local shop, and had the tech check to system for leaks. The guy has been working on my family's cars for several years, and has always treated us well. He used the dye stuff, and did a vacuum check, and an hour later he comes and tells me "you don't have any leaks. What's more, I put in the refrigerant, and the car has been running for 20 minutes with the A/C working perfectly". I was stunned! He told me that when I tried to use to self-charging can, sometimes they don't have enough pressure to fully charge the system. But more than likely it was due to the cap not sealing on the low pressure port properly, and the can simply bled dry. As I recall, the pressure gauge never did creep up above about 10 psi. He also said that both my compressor and condenser were both fine. He told me to drive it for the weekend to be sure, and if it continued to have any problems, bring it back. So as I drove home, I ran the A/C, and no problems whatsoever. If it needed recharging, he said it would be a total of about $60.

By the way, I think he took pity on me when I told him what I went through to get to this point, since he didn't charge me for the test. So now it appears that my A/C is fine. Total cost to me: $0. :thumbsup: