Broke into my stash of Delo 30 from the AZ clearance.
95 saturn sohc, 173k miles, burns a quart of no-matter-what every 700 miles.
Have run diesel 15w40s previously, April-November.
Previous oil (from winter) was M1 5w30 topped off with a quart of superflo 10w40.
Car usually sees either full syn or HDEO. Did see an auto-rx cycle with cheap oil last year.
The point... nothing! Runs the same on everything. Runs the same on Delo 30. No startup noise at around 48'F this morning.
Will report back if fuel economy suffers but seasonal changes in fuel, air density, warmup speed have traditionally eclipsed any effect oil choice has had on this car. 12 mile commute and the car is fully warm in 6 miles.