Well, the title explains it well enough, I believe. I'm running Castrol German 0W-30 in my 7M-GE, and I'm coming to the point where I'd like to change the filter (3000 miles). I've never changed just the filter. How much oil can I expect to lose between what's in the filter and what drains out? I'm guessing I should change it when the engine is cold, so that the oil is in a thicker state, and hasn't circulated through the engine yet. But, this is only speculation.