Good point.
Thats someting I forgot to ask Zach,
Are we talking about a R12 or an R134a system? I never thought to ask as it's been a long time since R12 has been in use, of course the 80 had a couple of years when it would have had R12 used in the A/C cooling system, as in most of the world production ran from 1990-1997, R12 was completely banned from production by 1996 under the Montreal Protocol for depleting the ozone. Most car manufacturers stopped using R12 in around about 1992 well before the total ban came into force.
I will admit, when I say I have been in HVAC-R for 40 years, that has been in commercial Air-Conditioning not Auto Air-Con, but the principles are the same when it comes to using a compressor in a refrigeration system, so everything I have stated in previous posts still stands, apart from the the type of refrigerant and oil used.
The process for using/updating a car cooling system with regard to refrigeration A/C from R12 to R134a is not an easy process as ther are many rubber parts in a car system that have to be changed, and the oils are not compatible as used in a R12 and R134a system, there are what is called in the trade 'Drop in' refrigerants but they are expensive, so the limiting factors are time/labour and gas costs.
So, to answer you question, no it's not just a matter of 'evacuating' a system that has been used with R12 and then recharging with the more mordern R134a.
Yes, you are right in saying the connection are different for the guage line to fit to from R12 to R134a, but the connections can be retro fitted.
I would also like to add, R134a is not the most 'up to date' Refrigerant used in cars A/C cooling, R1234yf has been in use since 2011. So there will be a cross over point in the 200 series range up for debate at some time in the future.
Hope all my ramblings make a little sense.
