If your Aerostar's AC needs recharging, you cannot use R-12. You must use a retrofit refrigerant, such as R-134a, along with the necessary components (oil and possibly an adapter or conversion kit) to make it compatible with your system. Simply adding R-134a to an R-12 system will severely damage it.
It's crucial to have a qualified technician perform this conversion. Improper conversion can damage your AC system and potentially create safety hazards. They will have the correct tools, refrigerant, and oil type needed for a successful conversion to R-134a.
