Originally Posted by i_isntreal
They probably have a removable oil pan. Kind of like a V8 where you have to put the piston on the connecting rod and drop it into the jug. Only it would be a bit more of a headache to get the top connecting rod bolt on/off. Nothing impossible, just a headache, and another specialty tool for the stealerships to sell.
Look at the pics - I can't see anything alike. No, just face it guys: you'll have to split the engine - take it out first - ... in fact, roll back the full factory assembling process, and then in reverse order ...
As has been said: this is what BMW is sure their clientship is alike.