You add refrigerant at the low pressure port but you do not add Freon. You add R134/134a. If you are having to add refrigerant then you have a leak that needs to be repaired first.
under the car behind the pass. tire
According the 1994 Acura Integra LS manual, recharge the system with Refrigerant HFC-134a (R-134a)
91 will have r-12 freon but can be converted to r-134a easily
It's a CFC refrigerant.
How many onces for 134A refrigerant does GMC Sierra use?
Yes. That is the ONLY refrigerant you should use in ANY vehicle with a model year of 1995 or later.