This oil came from a Mazda dealership. I requested that the dealership use synthetic oil, but I do not know if they did. Car was used hard. Lots of short trips (
Replaced with Rotella T6 5W-40 and an FL-400S.
I've had good results running Mobil 1 5W-30 and 5W-30 EP- even with a 7,500 mile OCI. I installed the Hypertech tune at 135,500 miles and that might have have helped a bit with respect to fuel dilution in the oil.