1999 Dodge Ram w/Cummins - Shell Rotella T 15W40

[Donald]

Oil had 7600, vehicle 169K. Mobil 1 filter Bteween .5 and 1 QT added.
Polaris comments: Magnesium is slightly high for this lubricant.

Wear metals
iron 16
Chrom 1
Nickel 0
Alum 1
Copper 0
Lead 1
Tin 0
Cadmium 0
Silver 0
Vanad 0

Contaminants
Silicon 5
Sodium 2
Potas 6

Multi Source Metals
Tita 0
Moly 1
Anti 0
Mang 0
Lith 0
Boron 43

Additives
Magn 100
Calcium 2263
Barium 0
Phos 1180
Zinc 1311

Contaminants
Fuel < 1 (estimate)
Soot < .1
Water < .1

Fluid Properties
Visc 100C 15.3
TBN 6.51
Oxy 15
Nit 7

Guess I could have gone longer. I changed to Rotella T6 and will UOA at 7500 before I consider a change. Walmart TC3 2 cycle oil added to the fuel (most fillups) at 1 oz/gal.

 

[chubbs1]

Looks beautiful! Funny, Polaris flags additive levels??

 

[dnewton3]

There was a LOT of life left in that load; very low wear and lot's of TBN and very low contamination. Probably could have easily gone 2x that OCI distance very safely.

You're going to have to run the T6 out WAY, WAY further out to make any decent ROI or you're just wasting money.

 

[Donald]

I emailed Shell and they agreed the Magn = 100 is high for Rotella T.

With the iron being so low is that because of a quality Cummins engine, good oil, good filter? All three?

I plan to start UOAs at 7500 for the T6 and go from there. What should the cutoff be? Any of the following Iron > 100, soot > 4, TBN < 2.

 

[dnewton3]

I do not recall the Cummins condemnation levels; I'll try to find them when I get a chance, but I would say your limits are reasonable. I would perhaps say soot at 3.5 and TBN of 1.0 or lower, but it is a bit of personal preference. Fe at 100 is probably reasonable. Cu might be 30; Pb perhaps 25?

Again, I'll see what I can locate.

 

[dnewton3]

found it:
http://www.calrecycle.ca.gov/Publications/Documents/UsedOil%5C2008020.pdf

look at page 11.


I was off just a bit on the Cu; at 20ppm. Soot at 3%.

 

[Donald]

So what is the consensus on the Magn = 100. Maybe it was the prior oil from the previous owner. But how much old oil is left after a drain via the drain plug and changing the filter. Maybe 1/2 cup. I cannot see how 1/2 cup out of almost 3 gallons could raise the Magn up by more than 1 or 2 PPM. Shell said the 100 was high, but did not (would not) say what it should be. I searched the forum here and did not see a VOA that had a Magn level from Rotella T.

 

[dnewton3]

Likely left over from a previous load? Or maybe even a tinge of "opps" that was put into the bottle at the point of packaging?

Bottom line is that it really does not matter, though. What is MOST important about the UOA is that it conveys two things:
1 lube health
2 equipment health

Both are in fine shape here. Your Fe is very desirable at approximately 2ppm / 1k miles, and the others are so darn low it's not even right to call it wear.

You could have easily gone 15k miles on that dino oil and probably not been anywhere near condemnation.

Extend your OCI, get the value out of your fluids. The T6 will have to perhaps play out to 28-30k miles just to break even for the ROI.

 

[Donald]

Lets say the prior oil had 200 PPM of Magn. And lets say there was 1/2 cup of old oil left after the drain. Add 3 gallons of new oil with no Magn. The new mix now has 2 PPM. The 3 gallons dilutes 1/2 cup by 96 to 1. So it brings down the 200 PPM to 2 PPM (roughly).

I do not know what the max Magn the prior old oil could have been. But it would have needed to be several thousand to bump up the Rotella T by any significant amount.

Sorry, but I am a math major so I enjoy numbers.

 

[Donald]

This post:

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2750798#Post2750798

has the Magn at 257 and reading the various replies, I think it was Shell Rotella T 15W40.

 

[dnewton3]

Donald - math major? Excellent! I do statisitical process quality analysis for a living. We have common ground.

But, let's not let ONLY math get in the way of common sense and logical application of our skills.

Mg is an input, not an output. I care little for add-pack inputs. Not that I don't appreciate them; I most certainly do. But I don't get all twisted about regarding which brand/grade has more of Mg, less of Ca, more of Phos, less of boron, etc, etc. INputs are only predictors of what might happen; outputs (wear metals) tell us what actualy did happen.

A great example is how some of the PCMOs have shifted away from ZDDP, and some brands have turned to boron or titanium. The wear results are still excellent, even though the traditional methods are being avoided.

RESULTS are what matters most.
This UOA shows excellent performance, regardless of the Mg issue. The Rotella TP gave excellent protection. You could have easily doubled the OCI.

To perform to the same standard, the T6 will have to push out the OCI to perhaps 2x further, and still give that same level of wear protection.

 

[Donald]

I agree its a great UOA, maybe the best I have done across vehicles. I intend to start the UOAs for the T6 oil at 7500 and then go maybe every 5000 until its contaminated. At least for my first run of T6. This truck is my daily driver unless there is snow and then I take the 4WD Jeep. I bought this vehicle 2WD so I could be assured it had never been used to plow.

 

[dnewton3]

It is a very good UOA, but to be honest I have seen better. And I'm not saying that you offend you, but challenge you.

Let me direct you to another Cummins running dino oil with a normal filter, and he's consistently extending his UOAs out methodically. See here:
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2480273&page=1

Now, he's running about 2.+ppm / 1k miles for his Fe; that is very consistent with industry averages and very predictable. His other wear metals are so low it's almost crazy. His TBN is still strong and vis is good, and his insolubles are in control. AND ... he is using dino Valvoline and NO bypass filter! He is approaching 20k miles on a dino OCI, and could easy go more. He's being very methodical and logical in his approach. If he can go 20k miles on dino with no bypass, then he'd have to go perhaps 40-50k miles on a syn just to break even!

So, that is why I say you are doing a decent job, but he has you beat. Consider it a friendly "challenge". The great thing about this "call out" from me to you is that if I'm correct, then YOU are the winner! If you approach this in a logical manner, you will be the one who benefits!

This is also why a cringe when I see people who use synthetics, and dump them at 5-7k miles. Somehow in their minds, they equate "waste" with "cheap insurance".

But facts and data do not lie; they will trump mythology and rhetoric every day of the week.

Can your Cummins do as well as his? Probably so. Can you get your value out of the T6? Only time will tell us if YOU have the ability to see it through!

 

[Donald]

Originally Posted By: dnewton3
It is a very good UOA, but to be honest I have seen better. And I'm not saying that you offend you, but challenge you.

Let me direct you to another Cummins running dino oil with a normal filter, and he's consistently extending his UOAs out methodically. See here:
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2480273&page=1

Now, he's running about 2.+ppm / 1k miles for his Fe; that is very consistent with industry averages and very predictable. His other wear metals are so low it's almost crazy. His TBN is still strong and vis is good, and his insolubles are in control. AND ... he is using dino Valvoline and NO bypass filter! He is approaching 20k miles on a dino OCI, and could easy go more. He's being very methodical and logical in his approach. If he can go 20k miles on dino with no bypass, then he'd have to go perhaps 40-50k miles on a syn just to break even!

So, that is why I say you are doing a decent job, but he has you beat. Consider it a friendly "challenge". The great thing about this "call out" from me to you is that if I'm correct, then YOU are the winner! If you approach this in a logical manner, you will be the one who benefits!

This is also why a cringe when I see people who use synthetics, and dump them at 5-7k miles. Somehow in their minds, they equate "waste" with "cheap insurance".

But facts and data do not lie; they will trump mythology and rhetoric every day of the week.

Can your Cummins do as well as his? Probably so. Can you get your value out of the T6? Only time will tell us if YOU have the ability to see it through!


I know its over thinking it. But it would seem to me the wear metals would need to be normalized for an industry comparison. I am assuming the iron is ring and cylinder wear. The normalized value would take into account the displacement of the engine and the capacity of the oil pan. Does a 5.9L Cummins diesel have that must less iron than a GM 5.7L gas, or is it that the sump is 3 gallons vs 5 QTs.

My goal on oil changes (extended and/or synthetic) is more to extend the life of the engine vs ROI for oil. Or to say it better, its ROI for the engine life vs ROI for the oil cost.

 

[dnewton3]

Applying the math in a statistical manner, yes, the "normalization" averages and standard devaitions all are accounted for in macro analysis. I have an article forthcoming in that regard. The "industry averages" are specific to the equipment; it's generally not a whole view of the entire diesel engine market.

Of all the equipment I've ever studied, nearly every engine has wear that is escalated near the front of an OCI, and then it settles into a fairly predictable negative slope.

The existence of low wear rates lasts a LOT longer than most folks would realize. There are two Ford/Connoco studies in the SAE logs that discuss wear as a function of the OCI. The most recent shows that even out to 15k miles, the wear rate was still dropping.

 

[Griz95]

Originally Posted By: dnewton3

Of all the equipment I've ever studied, nearly every engine has wear that is escalated near the front of an OCI, and then it settles into a fairly predictable negative slope.

That is interesting...one would think it would be just the opposite. With new oil, I would think the wear numbers would be less than after the oil has been used for a while. Is there a logical reason for this?

Griz95

 

[dnewton3]

Two reasons:
1) tribochemical normalization
2) residual oil at low OCI intervals

This combined phenomenon is proven in both UOAs and SAI studies.

But I do understand your revervation; it goes against all the programming we've been handed by oil marketing for decades.

Filtration, too, actually get "better" with age. That also goes against what the common thought would be. The filters get more efficient at trapping particulate as they load up.

Most folks always equate "new" with "better". But that flat out isn't the case for oil or filter.

I have an article forthcoming shortly; it explain in much greater detail.

 

[Donald]

Originally Posted By: dnewton3
Two reasons:
1) tribochemical normalization
2) residual oil at low OCI intervals

This combined phenomenon is proven in both UOAs and SAI studies.

But I do understand your revervation; it goes against all the programming we've been handed by oil marketing for decades.

Filtration, too, actually get "better" with age. That also goes against what the common thought would be. The filters get more efficient at trapping particulate as they load up.

Most folks always equate "new" with "better". But that flat out isn't the case for oil or filter.

I have an article forthcoming shortly; it explain in much greater detail.


But of course you want to change the filter the minute before it fills and goes into bypass. When would that be? Maybe a dashboard light?