Agree with all, and a tip
If you have air in system, you can keep trying to chase it out by repeated bleeding, or you can eliminate it, is what I was told and it worked. Note: I don't know a thing about these cars other than what I've learned from someone else, mainly this board, and most everyone on here knows more than me, but I'm sharing this cause it's not emphasized much, and it's worked for me.
Car on level ground, jack the rear high, drain coolant.
Lower the rear, jack the front high, then . . . pour coolant back in slow, slow, slow, slow. Ridiculously slow. Painfully slow. Lord, am I ever gonna get through slow. This helps to keep air pockets from forming.
Then Jim Cash bleed procedure. Once you get a stream of solid coolant, close bleed screw, but let the car keep running. Wait a couple minutes, try bleed screw again, you may get a few bubbles. Repeat until you don't. Drive normally, watching temp gauge, but you probably will be real happy.
Park on level ground that night, top off tank to cold mark the next morning.
Have changed 4 BMW radiators, and once I knew to add coolant Painfully, Ridiculously slow, have had no problems at all.
I still watch the temp gauge like a hawk.