Why didnt I read this thread before I did my last oil change. I went from normal oil to Valvoline's Synthetic oil and my car is at 99K right now. Is that considered HIGH mileage? I'm about due for another oil change in like 1 week and a half, so I'll probably switch back to the Maxlife 5w30. I wonder if I change back to normal oil, my valve cover would stop leaking a little....
