R12-r134
Do you know what's in freeze 12.........? Propane!!!! that's right and I don't want to be blown up in my car if I get a leak in the evaporator or any part of the AC system and there's an ignition source. i.e. smoking a cigarette, a spark.
Now you guys are making this whole thing more confusing and harder than it is. I converted my system to 134 years ago and I tell you it gets cooolllllldddd!!!! 38* vent temps at idle in 85* plus weather. What components did I change?... Nothing. I only added dual fans. Although I did have to eventually change the OE compressor which was 20+ years old anyway. Here is a detailed expalnation of what works and why and a how to for converting your system.
The main reasons your R134 system does not get as cold as your R12 are
1)condensor inefficiency. The fins are too big to properly condense R134 molecules therefore alot of heat is still left in the refrigerant after it leaves the condensor.
2) incorrect metering device (oriface tube) the factory oriface tube was designed for R12 therefore does not meter the correct amount of refrigerant to change the state of R134 from a high pressure gas to a very fine low pressure gas. The Ford oriface tube is a very good low cost idea but any auto parts store should sell or be able to order orifice tubes designed for extreme heat climates. These would probably work even better.
3) R134 operates at a higher pressure than R12 so you need to charge the system with 10% less than the factory recommeded amount. I'd go as far to say 12% less depending on your gauge pressure. This is the main cause of compressor failure, overcharging. The compressor is just a pump it doesn't know what you put in it. Then turn your low pressure switch down so that the compressor does not cycle off until it the gauge goes down to about 22-25 psi.
4) Air flow. Did you notice that as we switched to R134 many vehicles also started putting huge electric fans to force air through the condensor? So did I, do this and you don't need to change the condensor.....air flow is the real key!!!!
So what do you actually need to change. 1)Accumulator/drier 2)oriface tube 3) refridgerant. All this other stuff orings and oil and compressors are just overboard. A tid bit of information for you....an oring, is an oring, is an oring. The color designates size, standard or metric but any color will work if it is the right size...period!!!
Do not, I repeat do not flush your system unless your compressor suffered a catastrophic failure. The hoses on the R12 system are not designed to withold the tiny molecules of R134 and will cause microscopic leaks in the system. The oil that has been saturated into those hoses form a protective barrier against leaks. Flushing the system will remove that barrier. Unless you are changing the compressor also you only need to add about 2oz of universal refridgerant oil. If you can't find it in your local parts store 2oz of pag will not hurt your system at all. Evacuate your system if you have vacuum pump for 30-45 minutes.
Why would anyone put 8oz of oil into an existing system when the compressor itself only holds 4-6oz of oil and even when flushing you can't get the oil out of the compressor unless you remove it from the vehicle and physically drain the oil out. Even then you measure what you remove and replace it with the exact amount plus 1oz.
So I hope this cleared some things up for some of you that nay have been a little confused about this whole process. It does not have to be expensive or painful uless you want it to.
Pete
