Using a diagram from one of the online part databases (bmwfans.info)...the R134 connections are
#2 (pressure line) and #3 (suction line)...this lets me know that I'm looking for the "pressure line" (#2) if I want to fill, draw or evacuate the system:
Then using the online BMW TIS website for specific instructions...I entered info for an F06 M6 then typed
R134a into the search field which lead me to the information below:
https://www.newtis.info/tisv2/a/en/f...check/2SqAkeDI
Since I'm at work and drove the e53...I can't verify that the image below is a F06 M6...and based on the note found on the TIS website...the F06 requires removal of the righ intake port...so again, the image below may not be exactly accurate for your situation. Click the TIS website link for more details/info/etc.
Only F01/F02/F03/F04/F06/F12/F13 (N63) from 07/2012:
To access refrigerant line connections, the right intake port must be removed.