I'm now 2,000 miles into my second cleaning cycle, and I was wondering if there would be any point in extended it to 5,000 miles. Following a UOA, I've been told I'm wasting 'good oil' by changing it every 3,000 miles. I use a Group III oil (Motorcraft Synthetic Blend 10W-30), which is well capable of a 5,000 mile OCI. Should I just stick to the 3,000 mile OCI (driving just 500 miles more than the recommended 2,500 for the ARX application) for this application? I know ARX wouldn't harm my engine, but would there be a point?
Also, I check my engine oil on a regular basis (before starting the engine first thing in the mornig). Since I've started the second cleaning stage, there's been an improvement in performance. It just wants to go, and feels so much smoother at higher rpms. The last time my vehicle felt and drove like this was when I drove it off the showroom floor 9 years ago. But I keep noticing small black particles in my engine oil. When I cleaned my transmission, there were a lot of these black particles in the old ATF. Is this because I'm checking oil that's sitting in the oil pan, that hasn't been filtered, or am I just using a bad oil filter (ACDelco Duraguard)? Thanks!
I think that I would stick to the recommended mileage at least during this second cleaning phase. Perhaps you can run an extended rinse, before switching on to the maintenance dose which can easily be run for the 5000 mile OCI. The black specs are usually contaminants removed from the ring packs. They will tend to settle in the bottom of the pan until fully dissolved. With regards to specs in the trans, it is likely these are very fine and form a slight layer on the magnet, if so equiped.
