I wonder if MMC actually have a program to enable the ECU to open all the valves, whilst filling the cooling system, to prevent air locks. Well maybe, but I bet the dealers do not.
I was told by a Porsche technician when asking about the cooling system, that the Porsche computer has a special drain and fill the cooling system program so that the valves are opened in the correct sequence to ensure that when draining there is no fluid left anywhere and when filling it fills every part.
I share your concern that some dealers may not have the training to properly follow the procedure. Replacing a radiator would not, I would have thought, be foreseen as a regular service activity.
