Drive the car around and see how the cooling feels with the R-134 and go from there.
As far as the Freeze 12; yes, I would vacuum the system before filling.
Check and see if the oils in Freeze 12 are compatible with the ester oil you put in when you were doing the conversion to R-134. If not, flushing needs to be done.
At this point before considering the use of Freeze 12, ask others who have used it. There are a/c forum boards that you can get good info from.
It's alot better than trying this and trying that in order to get the desired results with you a/c system.
I agree-good plan. I have yet to actually drive it so it may do alright and not require any further action.
The Freeze-12 use has been long debated. I have heard good things and bad. I have actually added it to R-12 in a 1981 GM system with good results, but I can't say if that was a fluke or not.
The Freeze-12 is compatible with the Ester oil but my concern is whatever oil would be left over from the R134. I'm not sure if it is PAG and if so, how much would you get into the system with two cans of refrigerant? Ester is compatible with both PAG and mineral oils, but not sure about the outcome if the Ester had a little of both mixed in?
