The procedure Terry listed above is a good one!     Remember that ester oils are 100 times more hygroscopic (attracts water big time) than mineral oils.  This means that a deep vacuum is very important.  Don't open that oil before your ready to charge it, it soaks up water like a sponge!

 

As for the temperature difference between R12 and R134A, R12 boils at about -20 degrees F and R134A boils at about -15 degrees F.   So technically thats about a 5 degree difference but there are other factors that make them very compatible comfort wise.  

 

Its the boiling off in the evaporator that gives the cooling effect.  Heat travels from hot to cold so the heat in the cab is absorbed by the refrigerant in the evaporator (this is the guy next to the heater core) and discarded via the condenser (this guy hangs out in front of the radiator and no, it's not cool to write your name on the fins) where it changes back to a liquid and starts the process all over again.  The compressor keeps it all moving!

 

I know, way to much information......I love this stuff!!!  What can I say!!

 

 

I have the manual valves, duct work is good no blockage or holes. I'm going to play around with it this weekend, I suspect that my system may be overcharged.

Something isn't right with the fan, it never blew enough air from the start, connections, switches, AC controls etc were all replaced. The fan sounds like it's going great guns, but you don't feel any difference in the air flow between low & hi fan mode  

 

I converted and still got excessive heat.  I installed the NAPA valves, roughly $40.00 and installed reflectix, available from Lowe's/Home Depot - $25.00 aluminum under the carpet and found 3 nagging holes in firewall - sealed them with windshield rolled caulking - any parts store - $15.00.

 

Made a big diference!

 

good luck gurtz

               Eurodesk here, I have a problem with my blow fan, I think it's

               a electrical problem some times the fan works and other times

               it doesn't. I'll check all electrical connections and wires, do you

               have any suggestion about how to test out the problem? I

               want to try to fix this my self before I give up and take it to the

               shop. Thanks.   Marion

               Eurodesk here, I have a problem with my blow fan, I think it's

               a electrical problem some times the fan works and other times

               it doesn't. I'll check all electrical connections and wires, do you

               have any suggestion about how to test out the problem? I

               want to try to fix this my self before I give up and take it to the

               shop. Thanks.   Marion

Hey Marion. Usually when the blower motor works intermittently its bad contacts in the motor. When it doesn't come on give the motor a tap and see if it starts. If so the motor may be bad.