Hi All, I have a 1991 Chevrolet K1500 which I want to convert from R-12 to R-134a as the A/C blows warm and the R12 is hard to service especially if dye needs to be added to source a leak which this truck may or may not have. I was told by a mechanic to convert it over to the newer freon as the dye he will add is only compatible with the R-134a. I have advance auto parts store credit so I'll use them for the parts. I'll be buying this conversion kit: https://shop.advanceautoparts.com/p/auto...rm=r12+to+r134a I'll also need the 8oz. Refrigerant oil. Looking at the Advance auto parts site, they sell them with ester (no pag indicated on the bottle? - medium viscosity), Pag 46 (low viscosity), Pag 100 (medium viscosity) and pag 150 (highviscosity). https://shop.advanceautoparts.com/web/Pa...doExactFit=true Which would I need? Anything else other than freon is required for this conversion? Thanks for the help!