You are correct R134a really does not work as well as R12. Much higher head pressure. But since that is what is in there now I will go back with it. And Yes AC work really is not for Most DYI people. However I have installed many R134a systems in aircarft so it should be no issue on the car I have teh AC certivaction and the gauges so it should be no issue. Just need to get it evacutated first