15w-40 CJ-4
What ever brand floats your boat.
Because it floats your boat.

 

 

I ran 15/40 Rotolla for years, good oil but formulas have changed and prices escalated.

Traveller Premium All Fleet 15W-40 Diesel Engine Oil

meets all specs for the 7.3 and is a bargain.

 

Posted this in another thread a few weeks ago. Lube related wear shown in the second pdf linked.
I too wonder about the ck spec and haven't seen any used oil analysis here... I went to the motorcraft oil after the ck hit the shelves.
I put this together because i dont think this new oil list is just mumbo jumbo and is actually something for concern.
Lets take a look at what chevron had to say about delo 400 in the 6.7 test and why its not currently on the approved oil list. I'll put links at the end of reply.

Following is from chevron pdf,
"Ford’s own 6.7 liter diesel engine durability testing with early prototype API CK-4 formulations revealed accelerated wear on rocker arm fulcrums, pads and push rod ends that were not replicated in tests run with API CJ-4 oils."
https://go.chevronlubricants.com/rs/...-Statement.pdf

Ford has also made mention of a 1000ppm minimum of phosphorus in BOTH new and older engines with some included wear images in this pdf. The wear on those pushrod tips alone is enough to open eyeballs wide.
ftp://ftp.astmtmc.cmu.edu/docs/diese...4%20120616.pdf

Of course Fords testing was on the 6.7 but the wear items of concern aren't radically different from any other pushrod engine...
A quick search turned up some virgin oil numbers for oils that are *NOT* on the WSS-M2C171-F1 approved list, along with rotella t4 15w40 which did make the list.
The rotella has a good bit higher Calcium ppm than the other oils. Its Zinc and Phosphorus numbers are close to the 15w40 Blue Valvoline but its Calcium number is a good bit lower than the rotella. The other two oils have a lower than 1000 Calcium. It also looks like the rotella has moved to boron for some of the wear package.
With all this in consideration I'll stick to the oils on the approved list, Id also be careful about zinc additives as it may disturb the balance of the blended wear package and be counterproductive.
*EDIT* found results for motorcraft WSS-M2C171-F1 10w30 and added link for comparison
Ford Motorcraft Super Duty Formula SAE 10W-30
Shell Rotella T4 Triple Protection SAE 15W-40 API CK-4
Valvoline Premium Blue SAE 15W-40 API CK-4/SN
Mobil Delvac 1300 Super SAE 15W-40 API CK-4/SN
Chevron Delo 400 SDE SAE 15W-40 API CK-4/SN

 

Walmart Supertech 15w-40...still CJ-4, robust add pack, cheaper than other oils.

 

The modern CK-4 oil spec is for the sake of making the diesel emission systems work more reliably - but it throws engine wear under the bus. If I were a conspiracy theorist, I'd be in a tizzy over this - because Detroit would love nothing more than scrapped diesel engines by 200K miles. "Oh... it blew up on you? No problem. There are plenty more where that came from. Will you be signing up for the $20,000 engine, or the $70,000 truck?"

CJ4 was the last known good oil formulation, and it had plenty of ZDDP as an additive. Don't take any one person's word for it - it's too important to not look this one up yourself.

 

I am using Motorcraft with WSS-M2C171-F1 standard.

https://www.fcsdchemicalsandlubrican...archdiesel.asp

 

I fall into that category. Involuntary "cash for clunkers". I'll take my tinfoil hat off for a few hours and enjoy my family and a meal.

 

Not to jump on the bandwagon, but.....jumping on the bandwagon.....

 

My last oil change was Motorcraft.

 

Just for clarification on oil, The oil spec in my owners manual say to use WSS-M2C171-C. And I'm assuming the WSS-M2C171-F1 is just a newer version of the same standard?

 

 

 

I've been running CK4 for two or three changes now, and my UOA shows normal wear numbers, and the truck runs well.

I had my UOA posted in another thread about this awhile back, will see if I can dig it up or get my most recent one posted.