Hi new member here but I have always lurked. My wife has a 01 4.4 X5 bought it with 50k miles on it 5 years ago and it has been one of the coolest vehicles we have owned until recently. When it turned 100k miles a few months back it went all to pieces. My main problem is the Oil Separator or that is what I thought. It started doing this back in the warmer months before it got cold. I would be at an idle and it would start idling rough and kinda squeel under the hood then smoke would pour out the tail pipes. It didn't do this again for a month or so then it did it again. I looked on here and saw all the problems and symptoms of the OS and figured that was what it was. so I changed it Tuseday as instructed, done oil change ect. Took it on a 3hr trip this weekend and it was fine till I got almost where I was going and it did it again. It didn't do it all weekend til I was comming home about 2hrs into my trip and it did it again and then again now the valve covers are leaking. Could I have gotten a bad separator or is it another problem? I'm so aggrivated with it I'm about to trade it. Thanks