> From: FltSgt@xxxxxxx > Date: Tue, 20 Apr 2004 07:36:39 EDT > Subject: Re: IML: A/C Question > Reply-To: mailing-list@xxxxxxxxxxxxxxxx > Patrick > > So you want to use the R-12 'cause that is what it was designed for. Do you > also use straight weight oil for the engine? > > The point is what was availiable when "it" was designed. Good point from Rodger and Gabby and something to think about. The nice thing about upgrading or modifying "drivers" is it leaves more N.O.S. and good used original stuff for serious restorations. Radial tires are certainly an improvement over bias ply tires and I use them on my vintage vehicles. I have heard stories of some old style narrow rims distorting from the use of radials, but I have never seen that happen. I believe virtually any engine that originally used straight weight oil can use multi grade. At least those produced since the 1940s. There are a couple of problems, however, when using R-134a in some A/C systems designed for R-12. (A bit of "tongue-in-cheek" warning for some of the content below.) The heat transfer properties of R-134a and R-12 differ. R-134a usually needs a much larger condenser, smaller duct tubing and perhaps a higher velocity blower fan to keep the temperaure at the interior vents comparable to the original R-12 system. R-134a needs "barrier" hoses under the hood and, all other things equal, has a higher working pressure. In the extreme heat of the desert southwest, a large fixed blade non-clutch fan or supplimental electric cooler fan may be needed if you drive in heavy daytime traffic. There is a company in Florida that converts original R12 systems to R-134a, but I have also heard some R-12 systems work just fine with R-134a. I do know of a couple instances where original R-12 underhood hoses ruptured when the system was changed to R-134a and the original hoses were retained. Point is, I'd do some research before simply adding R-134a to an R-12 system or using one of those forty dollar "conversion kits." We "desert rats" take our A/C as seriously as any snow belt resident does his/her heater/defroster! ;-) Ken J. Las Vegas, Nevada 1968 Crown Four Door Hardtop