Great, someone else with a Diesel x5!!Why are you changing the oil after
only 2700???Oil service is done at 20,000k!
Anyway,to answer your question.On page 149 of your owners manual,
it tells you which grades of oil you can use,In fact,the Diesel uses the same
grade as the petrol versions.In all cases,the oil must be "longlife" and spec
must be ACEA/A3/B3/B4..,..B3 is a 15w-40 grade,B4 is 5w-40.The latter
is best for the car.Regarding makes,Bmw recommend Castrol (marketing
reasons.....they used to recommend Mobil1!!),but I prefer " Valvoline"!
the one to get is DURABLEND EXTENDED DRAIN 5W-40.(spec is ACEA/A3/B4).
Here in Portugal it costs 62 euros for a 4ltr container.You will need 2!!