2021 Chevy Duramax L5P - 19,000 miles/440 hours on oil - 21,500 total miles/495 total hours - HPL 5w-40

wwillson

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This is a 2021 Chevy 3500 DRW L5P Duramax that pulls a 20,000 pound 5th wheel for a combined GVW of 29,500 pounds. This engine has been consuming engine oil when pulling and I'm happy to report that pulling in 8th gear and increasing to 1850 RPMs has reduced the oil consumption to zero. All consumption occurred between 0-16,000 miles on this sample. See this previously posted thread:
The latest oil sample has 19,000 total miles on the oil. All other aspects of the oil looks good for continued service, however we set the condemnation limit at 100PPM Fe, so the oil was changed. I anticipate the next series of UOAs on this engine will show a decrease in wear metals, because of the decreased engine heat now that we are pulling in 8th gear and lower engine break-in metals.

Sample Information
Sample Date6/23/202107/17/20218/24/20214/4/20227/1/2022
Machine Age miles2,5002,7008,90016,00021,500
Oil Age miles2,5002006,40013,50019,000
Machine Time hours5562214350495
Oil Time hours557152295440
Filter Age miles2,5002006,4007,1004,000
Oil ChangedYesNoNoNoYes
Filter ChangedYesNoYesYesYes
Make-up oil0001.5 qts2.5
BrandFactoryHPLHPLHPLHPL
Viscosity15-405w-40 CK-45w-40 CK-45w-40 CK-45w-40 CK-4
Wear Metals
Iron1243667102
Chromium<1<1234
Nickel<100<10
Titanium<1<1<1<1<1
Silver3<1<1<1<1
Aluminum<10151314
Lead61243
Copper1092885188203
Tin61066
Vanandium<100<1<1
Additives
Boron1201512216
Barium<10000
Molybdenum2514450504537
Manganese<1<1<112
Magnesium6729959681008924
Calcium12602439241425572459
Phosphorus1000109910291064981
Zinc11551179114812851233
Contaminants
Silicon8733484654
Sodium75335
Potassium112435559
Fuel %<1<1.0<1.0<1.0<1.0
GlycolNEGNEGNEGNEGNEG
Soot%0.10.10.40.60.8
Fluid Condition
TBN8.5514.913.313.710.8
Viscosity13.914.513.814.9714.5

[edit - add pictures of oil filter]

This is a Fram Ultra XG2 and it's the hardest oil filter to cut I've ever attempted. I say attempted, because I gave up trying to cut the element completely out with a utility knife. It's the first time I've ever been foiled by an oil filter. The metal mesh backing is very difficult to cut with a knife and I didn't want to use a hack-saw, because it would introduce metal to the element. The filter is another fine example of a high quality Ultra.

There is some metal in the filter, but steadily declining since the first oil filter change. This is the fourth filter since new.

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As a long time lurker at BITOG, I remember Doug Hillary stating that 150 ppm iron was his condemnation point. And I believe this was in the context of severe duty diesel fleet useage. I am glad things are simmering down for you here.
 

wwillson

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Any concern for the potassium? It's leveled out but higher than initial uoa's.
Wearcheck flagged the report with a warning "GLYCOL", but glycol is negative. I was concerned, until I looked a many other Duramax UOAs on this site and many seem to have elevated potassium. We will watch it for now and do nothing until we see a reason to.
 
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This is a 2021 Chevy 3500 DRW L5P Duramax that pulls a 20,000 pound 5th wheel for a combined GVW of 29,500 pounds. This engine has been consuming engine oil when pulling and I'm happy to report that pulling in 8th gear and increasing to 1850 RPMs has reduced the oil consumption to zero. All consumption occurred between 0-16,000 miles on this sample. See this previously posted thread:
The latest oil sample has 19,000 total miles on the oil. All other aspects of the oil looks good for continued service, however we set the condemnation limit at 100PPM Fe, so the oil was changed. I anticipate the next series of UOAs on this engine will show a decrease in wear metals, because of the decreased engine heat now that we are pulling in 8th gear and lower engine break-in metals.

Sample Information
Sample Date6/23/202107/17/20218/24/20214/4/20227/1/2022
Machine Age miles2,5002,7008,90016,00021,500
Oil Age miles2,5002006,40013,50019,000
Machine Time hours5562214350495
Oil Time hours557152295440
Filter Age miles2,5002006,4007,1004,000
Oil ChangedYesNoNoNoYes
Filter ChangedYesNoYesYesYes
Make-up oil0001.5 qts2.5
BrandFactoryHPLHPLHPLHPL
Viscosity15-405w-40 CK-45w-40 CK-45w-40 CK-45w-40 CK-4
Wear Metals
Iron1243667102
Chromium<1<1234
Nickel<100<10
Titanium<1<1<1<1<1
Silver3<1<1<1<1
Aluminum<10151314
Lead61243
Copper1092885188203
Tin61066
Vanandium<100<1<1
Additives
Boron1201512216
Barium<10000
Molybdenum2514450504537
Manganese<1<1<112
Magnesium6729959681008924
Calcium12602439241425572459
Phosphorus1000109910291064981
Zinc11551179114812851233
Contaminants
Silicon8733484654
Sodium75335
Potassium112435559
Fuel %<1<1.0<1.0<1.0<1.0
GlycolNEGNEGNEGNEGNEG
Soot%0.10.10.40.60.8
Fluid Condition
TBN8.5514.913.313.710.8
Viscosity13.914.513.814.9714.5
What about if you need warranty service?
 

dnewton3

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The Fe is tracking with miles; around 5ppm/1k miles very consistent over the last three samples. The other wear metals are pretty much a non-issue. I'll be interested to see if the Cu comes down a bit; probably a reaction to the esters in the oil and likely will subside. I will also be interested to see how the Fe wear reacts to the lower gearing selection for the next sample. I concur with the OCI; 100ppm Fe is a decent condemnation point.

Overall a good effort!
 

OVERKILL

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As a long time lurker at BITOG, I remember Doug Hillary stating that 150 ppm iron was his condemnation point. And I believe this was in the context of severe duty diesel fleet useage. I am glad things are simmering down for you here.
Yes, he was running ~100,000Km/60,000 mile OCI's in 500HP DD OTR trains through the Aussie outback. His condemnation point for Fe was 150ppm, but often it was other things that triggered an oil change.

Pablo shared pictures of some liners and bearings from one of these engines after a routine tear-down and inspection at 1.2 million km (~750,000 miles) and the liner still had visible cross-hatching and both it and the bearings measured "as new" still. It was reassembled and returned to service. I believe the fleet testing ended at around 2.5 million km (1.5 million miles).
 

dnewton3

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The topic of wear metal contamination is often glossed over, but it's not that hard to understand.

There are two fundamental issues to discuss; a content limit, and a wear rate limit

Content Limit
This is what we're referring to when we say "condemnation limit" in this conversation. It's a nod to saying "There's X ppm of metal" (Fe, Cu, Al, whatever) in the sample, and we want to change the oil because it's become heavily loaded with the metal.

If the metal is a "soft metal" such as Cu or Pb, the presence of the metal may be telling of the inferred wear, but it's not really harmful in and of itself. The nature of the soft metal isn't likely to cause more damage in a matter of abrasion. This is a generalization, but it's reasonably accepted by many experts. If the metal is a "hard metal" such as Cr or Fe, a high concentration of these metals can become abrasive and actually accelerate the wear trend. This also is accepted by most experts, though it's not easy to discern exactly how much occurs. Many SAE studies have noted this phenomenon, though I don't know of any study which solely went after this topic. But it does make sense; hard metals will abrade other hard and soft metals. Also, note that soft metals can often see a spike that disappears in the next UOA sample; this is not common in hard metals.

And so, there's often a "condemnation limit" placed on the hard metals (Fe being the most commonly discussed) to indicate when oil should be changed. These limits often come from the OEMs because they either have internal data studies, or educated guesses from years of tribal knowledge. It's very common to see either 100ppm or 150ppm from almost any OEM (Cummins, DD, Volvo, etc). When there is absence of a stated limit (such as this Dmax in this thread; GM and Isuzu have never stated an Fe limit I'm aware of), then it's typical to accept 100ppm as the "limit".

If we had reams of data showing otherwise, that some other magnitude were acceptable, we'd use it. As many know, I've got somewhere around 30k UOAs in my database; probably 600+ are Dmax engines. However ... VERY FEW people ever run their oils out long enough to get 100 or 150ppm of Fe in their sample. And past that? Pretty much never happens. So, unfortunately, we don't have good data to say whether 200ppm or 300ppm is safe or not. IN THE ABSENCE OF GOOD DATA, I often will echo the generally accepted limit of 100-150ppm. Most folks need a "limit" to feel good about their decisions, and so that's the number where most "experts" will feel comfortable. It's not that 300ppm would be unsafe; the issue is that we have so very little data out that far that we cannot make any good conclusions from the data. For folks who are uneasy about experimenting with their personally owned expensive equipment, I can understand; they need a limit to feel they are doing right by their vehicle.


Wear-rate Limit
This is, by far, more important. The rate at which metals are shed need to be understood.
In this UOA series, the Fe is being shed in a very consistent manner; about 5ppm/1k miles across three samples. The escalation of Fe content seems to have no effect on the wear rate so far. If one was happy with the wear at 6.5k miles, and at 13k miles, then why be unhappy with the oil at 19k miles? The RATE of wear hasn't changed at all, despite the higher loading of the Fe content in the oil. How far will this continue? We don't know, because the "condemnation limit" (content) was reached.

If this were my Dmax (I sold my LBZ a few years ago), I would say as long as the WEAR RATE is going unchanged, then the condemnation limit can be set aside. I'm not advocating to ignore the content limit, but don't use it as the sole decision point.

If 100ppm is the content limit, how long does it take to achieve that?
If you hit 100ppm in only 5k miles, your "wear rate" would be 20ppm/1k miles; that's really high for a Dmax and might indicate something is askew. It would NOT make sense to keep using the content limit, because the wear-rate is very high. But if you hit 100ppm in 50k miles, your "wear rate" would be 2ppm/1k miles; that's a VERY good wear rate for a Dmax, and so if multiple UOAs show this wear-rate as consistent, I'd ignore the content limit.


Oil contamination
We all know that spectral analysis does not see all wear particles; it only sees those below 5"ish" um. And so, knowing that, we have to accept other means of quantifying oil contamination. Here is where we enter the topic of PCs (particle counts). PCs see ALL particles by size, but they do not establish material composition. UOAs see ONLY particles below 5um, but don't tell us particle size. PCs may see a particle at 10um, but they cannot tell us if the particle is Fe or an oxidation byproduct (soot). So it may be prudent to start getting PCs along with the UOAs, to understand the overall contamination load of the sump. SAE studies have shown that there is very good correlation between the UOA magnitudes of wear metals to the PC quantities in the same samples. When there are low counts in the UOA, the PC echos with low particulate loading across the spectrum. But now that we're getting into the topic of higher UOA content loads, it's very logical to presume the PC loads are going up correspondingly. Hence, the Fe particles we can see in the UOA (100ppm of the condemnation limit) are telling us there's probably a lot of Fe we cannot see above 5um. Still, as long as the WEAR-RATE is staying steady, it can be presumed that the amount of "damage" from the higher content load isn't affecting the overall engine health. If the wear-rate is at 5ppm/1k miles (as seen in the UOA) at 10k miles, and then it's still around 5ppm/1k miles at 30k miles, the unseen PC loading can be concluded to be ineffectual.


Summary
In the absence of good data, a content limit is in place, and the general long-standing limits are employed (100-150ppm for Fe). But when good-wear rates are present, and there's been no significant change in the wear-rate, that is telling us that the content load is not affecting the engine so far. When running extended OCIs, it's pragmatic to start stacking the deck in your favor. The more data you can get, the better. Because macro data is very uncommon at these OCIs, then you have to start collecting your own data. UOAs and PCs will help understand when to change oil.



My recommendation for this next oil load would be thus:
- sample every 5k miles (or as close to 5k as Wayne can get).
- track the PC loading
- track the UOA wear-rates of the metals; the Fe seems to be the most active
- only OCI when the wear-rate shifts in a significant manner (escalated more than 30% in one sample cycle)
 
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wwillson

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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Fabulous post @dnewton3

I will check to see if Wearcheck does particle counts and consider running until we see a spike in wear metal rates.
 
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This is probably some of the best legit advice I have ever seen given for UOA. If the wear rate is consistent keep going. Obviously looking at the other aspects of the oil as well. Condemning this sample while there is no increase in rate of wear was a premature change. That being said, this being a very early sample in the vehicles life. There was merit to change based on that factor. Using the data and a good common sense approach and REMOVING EMOTIONAL input allows us to make good choices.

Well done Mr. Newton.

David
 

dnewton3

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This is probably some of the best legit advice I have ever seen given for UOA. If the wear rate is consistent keep going. Obviously looking at the other aspects of the oil as well. Condemning this sample while there is no increase in rate of wear was a premature change. That being said, this being a very early sample in the vehicles life. There was merit to change based on that factor. Using the data and a good common sense approach and REMOVING EMOTIONAL input allows us to make good choices.

Well done Mr. Newton.

David
Thank you.

I will clarify one thing I think you probably would agree with, but I don't want it to go unsaid, so allow me to modify your statement:

HPL: "If the wear rate is consistent keep going."
DN3: "If the wear rate is acceptable and consistent keep going."

The key here is to make sure the wear-rate is good, and if it does not change much between sample points, keep the OCI going. I believe that you implied this, and I realize I'm nit-picking, but one should not continue an OCI if the wear-rate is bad, even if "consistent". Being consistently undesirable is not a good thing. For the heavy towing Wayne is doing, the Fe wear-rate is very normal and acceptable; 5ppm/1k miles is completely expected for what he's doing. But if he were driving unloaded all the time, cruising the highway at 1400rpm with low EGTs, the Fe wear rate should be much lower; between 1 to 2ppm/1k miles. So the magnitude of the metal wear-rates needs to be consistent with the expectation of the application of use. I'm sure you'd agree, Dave, but one should not continue to use oil if the wear-rate is bad; the sump needs dumped, and if prudent, some investigation into why the wear rate was outside the expected norm for the usage factor. When the wear-rate is acceptable for the use and environmental factors, and consistent from sample to sample, keep on using that oil !!!


Dave.
 
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