It all depends on where the leak is, and how big it is. Question is, if you refill the system yourself (which is pretty easy to do on most vehicles) how quick does it leak out and cause the A/C to stop blowing cold air?
Cans of R134a refrigerant are relatively inexpensive ($5-7 each)
at Amazon,
Walmart, or other auto parts suppliers. A refill on a completely empty vehicle system generally needs 3-5 cans depending on its capacity. You can buy a cheap gauge (or a can with a low-tech removable/reusable gauge
like this one, which is what I did) to measure and refill.
Last year, my Suburban's A/C was blowing warm air. I measured the system pressure and it had almost no refrigerant. I put several cans of R134a in (checking the pressure and the cold air output after each one), including a can of
this Stop Leak product. My Suburban has a rear A/C system with 2 blowers, and required 4.5 lbs of refrigerant (quite a bit) to be full... that info came from the owner's manual. The A/C worked great all last summer, and is still blowing cold... so I guess the leak was pretty minor and the Stop Leak product worked for now. I'll take it!
If you can refill yourself each season for about $20 of refrigerant and maybe 20 minutes of your time, that's a WHOLE lot less than paying $1500 for a new compressor, evaporator, lines, and shop labor. It's worth trying at least once IMO, to see if your system will hold the refrigerant.
