The 1988 Pontiac Bonneville originally used R12 freon, this freon is no longer available due to government regulation. Your A/C system must have it's A/C service ports replaced. Then the system filled with the correct amount of R134a freon.
134a.
It came from the factory with R12 Freon. It may have been converted to R134a. If so there should be a sticker near the compressor. If it has not been converted, I suggest you do so, as the price of Freon is prohibitive.
R134a
About 17 mpg (city)
a supercharged muscle car engine
OEM refrigrant was R12 unless it has been converted to R134a.
R134a
1985 Pontiac bonneville,1998 Ford Wind star
R134a
R134a
R134a