R134
THERE IS NO FREON IN A 98 IT IS R134
Freon is R12. Your 1997 Chevy uses R134 Refrigerant.
It does not use Freon as a refrigerant. It uses R134 refrigerant.
R134 .... IS freon.
R134
There is no need to ever change the refrigerant which is R134 and not Freon R12.
They should never be mixed.
1993-95 for most.
It came from the factory charged with R12 Freon. As this refrigerant is extremely expensive and hard to find, I suggest you convert it over to R134 Refrigerant.
R134
R134