There is no need to ever change the refrigerant which is R134 and not Freon R12.
1994 Chevy lumina freon type
Fittings for 134 freon
Connect the Freon bottle to the low pressure port on your air conditioning compressor. Release the Freon into the compressor. The purchase of a Freon recharge kit will make the process quite simple.
Chances are your leaking freon. There may be a leak in one of the seals.
R134A
R-12
No. You are looking at the wrong port. If you are looking down at the port you see, look past it to the left, beneath the air cleaner.
Where do I put freon in a 2007 chevy impala
Should be a valve like a tire valve on one of the lines near compressor. Use the one with a blue color code (low pressure side)
How much freon does it take for a 2000 Chevy full size truck
R-134 Refrigrant.
Freon is R12. Your 1997 Chevy uses R134 Refrigerant.