I was running Rotella T6 5W-40, but that was before CK-4 oils came out. I still had a pretty good stash of CJ-4 oils to work with, but I've only got enough for one more oil change.

I'll steer clear of CK-4 oils. Next time I buy oil, it'll be Schaeffer Supreme 9000™️ Full Synthetic Oil 5W-40, it's still CJ-4, for now. If I'm on the road and need oil, I'll stick with the WSS-M2C171-F1 oils with the Motorcraft logo on the bottle.

For filters, here's what I've found...
The absolute most efficient primary lube oil filter you can get for a 7.3 is the Donaldson DBL7405. (intended for a Caterpillar 3406) It's rated at 7 microns nominal, and 15 microns absolute. But this filter gets dented by my front suspension when it flexes, so I don't run it anymore.

The second most efficient filter I can find is the Donaldson P550371, it's rated at 17 microns absolute.

The third best I can find is the OEM Motorcraft FL-1995, according to Ford's website it's 18 microns absolute.

There's a lot of hype about the Wix 51734XE & Napa 1734XE oil filters, but the published beta ratios are 4 @ 10 microns (absolutely incredible) and 75 @ 30 microns (less than mediocre). I'm inclined to think they've mistyped something because that's a wide range of good-to-bad performance in a single filter.

And unfortunately quite a few CK4 oil’s are under 1k of zddp to help cat/DPF life.

Some are still ok.

At a 20K OCI with a good quality synthetic, I wouldn't be worried about engine wear... I'd be worried about the depletion of the anti aeration additive package and the reduced performance of the oil... not as a lubricant, but as a hydraulic fluid providing the motive power for the injectors... where entrained air from the constantly churning oil would likely reduce the effectiveness of the oil's hydraulic function. Not a concern in a common rail fuel system, but something that International often said is a concern with a HEUI system.

late to the party but I use chevron delo from walmart, Mobil delvac is also very good and is now cheaper around $10/gal. I used rotella when i first bought my truck in 06 I like chevron/delvac much better. made my engine louder/noisier. won't touch the stuff after.

Big R, tractor supply, etc have sales on mobile delvac where you can get it extremely cheap if you can afford to buy by the pallet. I use baldwin filters but would prefer fleetguard or donaldson...just my opinion

You have found a good price...Lol

No UOAs to report. I did some a while back and things were fine but anymore I'm just going by what I feel is a good, conservative time and mileage frame for what most people running full synthetic and bypass systems do. Motivation? I was motivated primarily by wanting to cut down on the amount of supplies I had to haul down here (Mexico) to change the oil and filters. One full oil change every 20,000 is a lot less oil and filters than every 5000 as I was doing before. It does come out a little cheaper, too, which is a nice side benefit but not the primary motivation. Also, I like having a high quality oil in the motor and the Mobile One filters have a better filtration rating than the OEM Ford ones IIRC. I also like the cold weather starting ease that comes with the full synthetic oil as well. And, yes, according to the manual my conditions are "severe."

Through Employer?..... Lol
It's really no different than any of the other big names.
About $150 for a 5 gallon bucket shipped to my door in 2-3 days.

Sent from my SAMSUNG-SM-G930A using Tapatalk

Do you have any UOAs to post?

Is your motivation cost savings?

IIRC, your driving conditions are “severe” as defined by the Owners Manual?

Thanks

I hope you get this through your employer at some kind of discount.

Its expensive.