Q: AC blowing hot air - 1998 Honda Accord

Odds are that your A/C system has a leak somewhere. If it needed refrigerant in the first place, then you added some and it’s blowing warm air again, that’s a fairly good indication of a refrigerant leak. The best solution is to have it dye-tested. The system will have to be vacuumed down and a light charge of refrigerant with fluorescent dye added along with it. If the leak is large enough to occur overnight, then it should take no time at all for the dye to be visible with the black light. To have this checked by an expert, consider YourMechanic, as a certified technician can come to your home or office to have the AC issue inspected and corrected.