Thanks Graham. My trips are both long and short. That said my 740 did not seem to have any problems being driven in this cold. I do not expect the separator it to last forever and I intend to put in new ones if I buy any X5. My biggest concern now is would it be so gone that even if I replaced the oil separator and the CVV diaphragm is changed the end result would be the same disaster?
I am getting it checked by an authorised dealer of course and would demand a warranty from the used car dealership.
I have also started to look at at the Touareg since then. I know that there are not the same but unless I can a clear idea about these problems I am scared to buy a X5.