In my daily driver, '99 Crown Vic 4.6L (ex police car), I usually run Chevron Supreme 10W30. I did two Auto-RX cleanings. One at about 100K miles and another at 110K miles. This time immediately following a 4K rinse cycle (I rack up miles quickly and ran the rinse longer than I would have liked) I switched to a homebrew to use up some old oil. My home brew is 4 quarts of Redline 5W30 and 2 quarts of Mobil 1 5W30. All of this oil is approximately 1997 vintage. I'm using an Amsoil SDF-11 filter. I plan on running this oil for 7500 to 10K -- definitely through the winter. I was amazed at how quickly this oil turned brown. At 500 miles it was noticably dirty. Now I have almost 1K miles on the oil and it is black. Like people here say over and over, Redline really is an agressive cleaner.