How many cans of 12-ounce, 134a auto air conditioning refrigerant is needed to

[babeboomer]

recharge 1991 Pontiac Firebird? Local garage says it usually takes 2 to 3 cans at about $9 each and $10 to put it in?

ALSO: The one can I bought says do not mix with refrigerant 12? How do I know what was in there? I believe we found out that my car "calls" for 12 but I am unable to find it? The auto parts store says we can use the 134a.

I"m really getting confused about all this. Can someone give me some correct answers and advice?

 

[Zimgxp]

The system originaly used R12. You need to do a conversion to 134a. R12 may still be available, but it is way expensive. Your best bet is to take it to a shop and have it done.