I finally found a UOA of a 7.3 running Rotella 15w40 with 2 qts MMO for 5K and his results were excellent - it's on the MMO forum by "SuperDuty":

*****
magnesium,phosphorus and zinc are lubricty additives, when those numbers are pretty good, you know things are well protected along with TBN number. Here’s my UOA with 15-40 rotella with 2 quarts of MMO. Its from a 7.3 Liter powerstroke turbo Diesel with 180k on the engine and 5k on the oil. Blackstone said my wear was slim to none. Keep in mind I have a 15qrt sump.
oil/ universal average
Aluminum 1/ 2
Chromium 0/ 1
Iron 8/ 17
Copper 1/ 4
Lead 1/ 4
Tin 1/ 1
Molybdenum 8/ 23
Nickel 0/ 1
Maganese 0/0
Silver 0/0
Titanium 0/0
Potassium 5/2
Boron 45/84
Silicon 3/9
Sodium 2/4
Calcium 2279/3107
Magnesium 7/88
Phosphorus 1083/1117
Zinc 1262/1293
Barium 0/1
SUS Viscosity @ 210 F 72.8/ 69-80
cSt Viscosity @ 100 C 13.68/ 12.7-15.8
Flashpoint in F 425/ >410
Fuel % <.5/ <2.0
Antifreeze % 0.0/0.0
Water % 0.0/0.0
Insolubles % 0.2/ <0.6
TBN 7.0
All my fellow diesel folk freak out when I tell them I use MMO in my oil. Then I show’em my numbers. No arguments after that!!!!
Main thing is that if your lubricty additives are good, and your insolubles are low, you can extend your drain intervals and save some coin. ******




It doesn't seem to have hurt anything...whether or not it helped ???

 

Ok, put my money where my ???? is and drained my oil filter and added about 2.5 qts MMO to the Delvac 1300 that has 3596 miles on it...I'll run that to 5K which should take me thru our cold weather and then change it out with straight oil...nothin' like seein' for yourself how something works..or don't...

I appreciate all the replies and welcome more insight on the "Mystery" !

 

I appreciate you taking the lead on this. Reps will be sent... I will be eager to hear the results.

 

I drove it Saturday on a short run and everything was smooth...seems as though the engine ran quieter from startup as opposed to having to warm up for a longer while before quieting down ... so far so good ... this winter will be my first with a diesel engine and I'm curious to see how it does as the temp falls below freezing and into the teens or lower...

 

***UPDATE***

Well, it's been 4 months thru our "winter" and 1325 miles since I changed out 2.5 qts of oil for MMO and all has been well. I've had no consumption and did not use my block heater at all and had no problems starting at 20*F. I did not tow during this time and most of the time it was run on the 80HP Daily Driver setting on my KT Performance (PHP) chip. I try to drive conservatively and during this time most trips consisted of between 30 and 90 miles one way with one 200 mile trip in the mix since the MMO was added - about 80% hwy miles...

This was my first winter with a diesel so I don't know if it's normal for the 7.3 to crank easily at 20* without plugging in or not ... had it stayed below 20* I would have plugged in to help save the fuel from gelling but that didn't happen with our mild winter....I also used Power Service in the white bottle mixed with a little of either some MMO or TCW3 @ 3 oz PS + 2 oz of TCW3 or 3 oz of MMO (or a mix of all three @ 3+1+2) per 10 gallons of diesel...

I'm coming up on 5000 miles on this oil and it has been just over a year since it was changed...it used no oil during the 3596 miles before MMO and none since it was added.

I've witnessed what MMO has done to clean and let things run better that I and others have used it in and can only think that it has help to keep this engine clean as well ... I've certainly not experienced anything negative during this use and will use it again next winter to do a little more cleaning and to thin the oil down for the cooler temps...

I do a drain and refill on the tranny with the oil change and will add 1/2 qt MMO to the ATF this time to do a little cleaning in there as well...

Truck is just about to hit 167,000 and so far - so good! Now, if these dang fuel prices will just come back down....

 

***UPDATE***

Changed the oil last night with 5,960 miles on this interval with 2,364 miles of that with 2.5 qts of MMO mixed in with no oil consumption during this 16 month interval...truck has 168,000 miles on it as of now. This OCI used Mobil Delvac 1300 with a MotorCraft 1995 oil filter and the same was used again. When cold weather comes around I'll drain the oil filter and refill with MMO as before. I also drained and refilled the trans but did not add MMO to the tranny at this time because it appears to be "full" after adding 6 qts of ATF - if level drops after driving, I'll add up to 16oz of MMO...

The use of MMO in my truck's engine appears to have been of benefit, if for no other reason than helping cold starts this past winter...I had thought that some consumption might would occur, especially when the temp went up, but fortunately, it did not...

As Always, YMMV ...

 

Thanks for the update. I am glad to see this is proving good.

 

I remember my old time commercial fishing buddies would run a 10% diesel gas solution in the winter for easier start up. They wanted their engine to start!! The fuel tanks were 2-300 gal. Tanks. I realize the old Cummins and jimmy's are a different breed an don't have electric fuel injectors. Probably had something to do with the horror stories of a runaway diesel.