[JimD]

I have a 2009 128i convertible with the normally aspirated n52 motor. Even though it is not my daily driver it is out of warranty by both years and miles, at about 55K miles. I change every 5K miles because it is plenty often enough, it takes me about 9 months to put on 5K miles, and it is easy to remember. My last oil change, I learned something interesting.

I only had one 5qt of Castrol 0-40 European and had always found the level almost over full after adding around 6 qts. So I tried dumping in the 5 qt and checking the level. It was right at the mid-point. I try to keep a quart in the trunk but I plan to keep using a 5 qt for oil changes with the option to put a bit more from the quart in the trunk if I need to.

Using only a 5 qt cuts the cost for the oil change to a little over $30 ($10 for a Mahle 816 filter and a little over $20 at Walmart for the oil).