I have a 2001 Honda civic. I recharged my ac with refrigerant but it only last about 3 days before the cold air stop blowing. I assume this would mean that the leak is pretty bad. Air is still blowing though. Would the best option be to run the dye to find the leak and then seal it if possible or replace the part? I really don't want to take it to a mechanic and be charged 200-300++
yes, A shop will just be filling your system with refrigerant and dye, then run your a/c for a few hours and look for the source of the issue.
Typically, before you can fix anything AC related you need the system to be vacuumed, so your not expelling refrigerant into the air. Even if it is leaking out, there is usually still a bit left in the system.
2001 are new enough they are switched to the new Ozone safe refrigerant that you can buy over the counter. I personally buy a bottle of AC PRO with stop leak. They seem to have the best chemical mix/ stop leak. Then when I know its holding a charge, I buy the cheaper Frost refrigerant. You are getting what you pay for refrigerant wise... It also can take a couple of weeks at full pressure to rejuvenate the seals and get them to seal properly again. I recommend to add better more expensive brand. If all fails buy green die/ stop leak. This is hard core stop a leak with neon green glow in the dark dye to help detect if one of the threaded connection is lose and needs tightening.