Doug,the change took place in the early 90's,my old lincoln a 93 was the last year they used R-12 I think it varied by manuf.It should say somewhere under the hood what it uses.If it has large fittings for quick hitch filling, its 134 if their small threaded with a tapered tip its R-12.Oh by the way the old Linc still has 12 .Frank C.