I did an oil change over the weekend and I believe I can shed some light on the subject. I discovered that if you do an oil change in the conventional way -- drain the oil, replace the filter, refill the oil -- you will have a problem. When you un-screw the filter housing, it will release almost a quart of oil back into the oil pan! If you don't account for this you will be over-filled if you put 8 quarts back in.

So, to make sure you get all the old oil out, do it like this:

1. Unscrew oil filter housing to break the seal.
2. Drain the oil.
3. Replace the filter.
4. Replace the oil.