Freeze 12 recharge

[Afredo]

Hey guys, bought a freeze 12 recharge kit (includes two cans of freeze 12 and one smaller can of oil I guess?) as my A/C no longer blows cold. What is the procedure for recharging my system with this? Do I have to drain the system of the old R12 first or can I just go ahead and charge it with the freeze 12? Do I need to use both freeze 12 cans or is one just an extra? And do I need to use the oil can at all, some of it, or all of it? And does it matter what order I use the oil and freeze 12 cans in? Also, if anyone could tell me where the low pressure port is located that'd be great. Its an '89 325i coupe.

[jlevie]

The right way to do this is to pull the R12 charge and recover what comes out. Remove the compressor and drain the oil out of it and refill with the correct amount of new oil. Use A/C flush on the lines, evaporator, and condenser to get any old oil out. Replace the expansion valve and dryer and use new R134a o-rings on the hoses you disconnect, pull a vacuum on the system for at least 45 minutes, and charge by weight. I don't know how much Freeze 12 is equivalent to the R12 charge (2.15lb).

The low pressure Schrader valve is in the large line that runs from the firewall to the compressor.