OK I know this is a borad question but hope someone can help. I have an 89 740 with the r-12 system. Was not working well when I bought it so having my epa card already I got a can of r-12 and charged it up. Has been working half way. Does not get cool at idle but had been freezing you out at highway speeds. Now it's just ok at highway speeds. My question is what is the ideal low side pressure for r-12 on this car with the aux. electric fan running at idle and about 95 degrees outside. I am going to do the conversion sometime in the near future but still have r-12 left so I wanted to see what I do until then.