In no particular order ....
1)
2) Any Dmax, I don't care what generation, wears well. The wear rates here are good, but they are not by any means different from what we'd expect to see, especially for a shorter duration.
3) Which "Mobil 1 ESP" is this? Are you referring to the PCMO (I hope not). Probably the Mobil Delvac 1 ESP in 5w-40? Pricey stuff!
4) Extend your OCIs. I doubt you came close to hitting the IOLM limit at 6k miles, did you?
5) 1/2 qrt oil use in 6k miles is totally and completely OK and not at all a problem. Relax your posterior and breathe a sigh of relief; there is absolutely nothing to worry about here. Long ago GM had a statement out about oil consumption; essentially anything less than 1 qrt per 100 gallons of fuel used is OK. Most Dmax engines run less that that. You will likely find that the oil consumption will follow the fuel consumption rate. Towing will cause the oil consumption to go up a tad, whereas unloaded running will cause it to be lower. I've never really seen a Dmax with a systemic oil consumption issue.
6) These engines just don't care what you run in them as long as it's a properly selected API lube for the HDEO application (CK-4 for yours; or a lube that is warranted by the maker for that application ala Amsoil and others). They show no preference lubes (or filters for that matter). I mean NONE WHATSOEVER. You're wasting money on such short OCIs with such expensive lubes. And before you begin type the "
It's cheap insurance" excuse, let me tell you that I've got far more data on Dmax engines than you'll have in your lifetime. No matter how much you wanna "
Yabut" (yeah, butt ....) this, it won't change facts. Dmax engines show essentially no reactionary trends in macro data sets for any type of traditional input (brand, grade, base stock). It does not get anywhere cold enough in TX (even in the north panhandle) to warrant the "need" for a 5w-40 expensive PAO. I ran 10w-30 HDEO conventional Rotella T in my Dmax long before it was a popular trend. I logged tens of thousands of miles on that lube choice. From colder weather than what you'd see, to the desert heat of AZ and UT, pulling my RV up the Rockies, etc. I've flogged my Dmax mercilessly with EGTs maxed at the OEM limit for LONG uphill pulls. And yet with every UOA, totally normal (and excellent) wear trends. My point is that ALL Dmax 6.6L engines wear well, and your results here are not good because you used a super-duper syn; they're good because Dmax engines rarely ever have a bad one, regardless of what's in the crankcase.
Recommendation:
- ditch the expensive lubes and get any decent 10w-30 or 15w-40 conventional HDEO you can find on sale, BOGO, rebate, etc
- follow the IOLM
- do not fret oil use unless you're at a rate greater than 1 qrt / 100 gallons fuel
- don't pay for TBN; it's not been shown to be of value in "normal" OCI durations because there is no correlation between TBN and wear trends up to 15k miles