Ok I have heard many different things about the air should I evacuate the old freon and oil and just have r12 and the oil put back in. Or should I try the pep boys 134a kit they say all you have to do is evacute the old freon and oil and change the o rings and install the new 134a compatable oil and 134a. Or would you recommend just filling the old freon add like a pound or 2? If you know a good bmw mechanic some advice would be real great or just email jeeperpimp2000@yahoo.com