bravo, nice explanation, Patrick
some poeple still believe that if they omit the thermostat they get a better cooling. But that is not the case with the BMW system.
Here a drawing of the coolant circuit of the V12 engine
BTW, Patrick: did you already buy a new heater core and the plastic pipes from there to the connection at the firewall? Where and how much? We have to change them too on the Alpina B12 "Take" (Mitsu) got 2 weeks ago. Just a slight coolant smell at the moment, no noticeable coolant loss too, but we want to fix it before winter comes.
Take has done it on his Highline last year, I posted some pics on BB, he says not so difficult, he did it in one week in the evenings, totally 5-7 hours he says. Shogun's E32 Tech Tips: http://tridem.han-solo.net/auto/erich/auto.htm