Recently i have been wanting to do a Coolant change on my 535D. I taught this would be simple but it appears not to be the Case. I removed the Lower hos from the Radiator and only about 1.8 ltr came out . Can Someone guide me into what needs to be done in order to get rid of the Old coolant and replace it with the New . My car has no electric water pump, Radiator drain etc.

 

You only drained the radiator. You need to also drain the engine block.

 

IIRC (been a while since I sold my E61) if you pop the cap off the coolant reservoir, it'll allow the block to drain. Or at least a whole lot more coolant to come out.