OP, I just purchased a 2012 Focus and will be installing a bypass filtration system to remove finer particles (wear metals and contaminants) from the engine lubricant. Not only will it extend oil change intervals, but will significantly reduce engine wear. Full flow screw on premium filters alone will not perform efficiently under 20 microns. Cheap filters aren't great under 30-40 microns. Bypass filtration systems will filter efficiently in the 1 micron range.
The bypass system will effectively allow my engine to achieve 15,000 mile oil change intervals, or one year, whichever occur first, on true synthetic lubricants. Also note that this is for a severe service schedule and would be capable of more. However, I believe that once a year oil changes are sufficient to save money, time, and the environment with less waste oil.
Look for a detailed installation thread in the coming weeks for the bypass filtration system with used oil analysis reports.
We were oil crazy on the GT500 forums, and I even created a UOA chart to compare results. Needless to say, Motorcraft 5W-50 is not a great lubricant. It rapidly shears to a very light 40 grade lubricant and shows elevated wear metal ppm.
The moral to my post, 3,000 mile oil changes are a waste. TBN (detergent and dispersant additives) is still plentiful in engine lubricants, even cheap oil, after so few miles.
Originally Posted by dyn085
At 10k I switch to Mobil One full synthetic with OEM filter and switch to 10k oil changes. That being said, I do replace the filter halfway through and top off with fresh oil.
Mobil 1 actually isn't a "true" synthetic lubricant. It's a blend of group III hydrocracked (i.e. highly refined petroleum) and group IV PAO true synthetic. Like Castrol and other big oil companies, Mobil 1 isn't 100% pure.