Engine coolant question!

[boxednfresh]

hi there, noticed one day that the engine coolant tank was empty so tookit to a mechanic, who decided to put sum water in it to see if the level wud go dwn again. He filled it up and after a while i noticed that the level dropped slightly after a few days of not driving the car. now its held its level at the max. Initially the tank was very dilute because of the water but now has become the conc green colour.

prior to this i bought sum engine cooant from bmw and it seems to be of the blue colour. i asked the guy is this for a mini and he said yes. is this correct??

Also i was wandering can i just remove sum of the engine coolant from the expansion tank via suction and replace it with the bmw engine coolant?

Also do i have to premix this bmw coolant before i place it in the expansion tank

iv looked aroudn for this answer but cud not find it, although the sticker on te bottle dus suggest sum dilution but was confused with the temp section.

thanks for ur help in advance.