what oil for 4.4l??

what do you use for your 4.4l bmw engine?2003-2005
is non syn. okay to use??

BMW recommends 5-50 Castrol full synthetic. Honestly, I wouldn't use anything but a full synthetic in that engine. It's got enough sludging issues w/the synthetic. BMW recommemds an oil change every 15K, which is stupid in my opinion. Especially since they say burning a quart every 1,000 miles is normal.

thank you!