2024 Tahoe LM2 Duramax 27.3k mi; HPL Dexos D 5w-30 12.2k mi; excessive Cu and Tn

wwillson

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2024 Chevy Tahoe LM2 Duramax 12,196 miles/252 hours on oil - 27,296 total miles/569 total hours - copper and tin in oil

This is the last UOA from my 2024 Chevy Tahoe 3.0L Duramax diesel engine. This engine had a faint lower end knock that I would listen to when I pulled it into the garage. At first I wrote it off to the fact that it's a diesel and diesels make knocking noises. When I got the last UOA back I about fell out of my chair. When I cut the oil filter I did fall out of my chair.

The UOA shows a rapid increase of copper and tin. The copper isn't coming from the oil cooler because it is all aluminum. The turbo has ball bearings, so no copper or tin there. After doing a lot of homework on where the copper and tin are coming from the only place in this engine that could be the source is main or big-end rod bearings.

I dumped the oil and cut the filter. Folks that is the second most metal I've ever seen in an oil filter. Not big chunks, but tons and tons of copper looking flakes and some slivered iron. The copper looking flakes are from the tri-metal bearings and the iron slivers are from the crank. There isn't any place else they could be coming from. The pictures of the metal in the filter element do it no justice. Digital cameras can't capture the sparkies like the human eye can. I'm going to keep the element in a zip-lock bag as a trophy. I never thought this would happen to me.

This engine has been making copper and tin from the moment it was first stated. The UOAs clearly show what's been happening.

Had I kept driving this motor, it certainly would have suffered a catastrophic failure. This was a manufacturer's defect and I wasn't willing to chance GM not honoring the warranty. I traded it for a 2025 Tahoe exactly equipped, except with a 6.2L gas motor.

Previous UOA here

Sample Information
Sample Date5/4/20245/5/20249/22/202410/13/202401/06/202504/29/2025
Machine Age miles3,0003,05013,69015,12520,65027,296
Oil Age miles3,0005010,640255,55012,196
Makeup oil quarts total00100.251
Filter Age miles3,0005010,640255,55012,196
Oil Changedyesnonoyesnono
Filter Changedyesnonoyesnono
BrandOEMHPLHPLHPLHPLHPL
Viscosity0w-20 Dexos DHPL 0w-20 Dexos DHPL 0w-20 Dexos DHPL 5w-30 Dexos DHPL 5w-30 Dexos DHPL 5w-30 Dexos D
Wear Metals(ppm/1k miles)
Iron38(12.7)7(0)69(5.9)9(0)29(3.6)52(4.6)
Chromium<1<11<1<1<1
Nickel<1<1<1000
Titanium<1<10000
Silver6<15121
Aluminum431171216
Lead<1<10<100
Copper1029312154289
Tin2<14<1721
Vanandium<1<10000
Cadmium<1<10<100
Additives
Boron4010670897461
Barium321004
Molybdenum277174638071
Manganese2<12<11<1
Magnesium1587610658471018964
Calcium17811167138796811521017
Phosphorus879798769664696605
Zinc927821907762832735
Contaminants(ppm/1k miles)
Silicon104(35)23(0)44(2)1418(0.7)17
Sodium202221
Potassium532022
Fuel %<1<1.0<1.0<1.0<1.0<1.0
GlycolNEGNEGNEGNEGNEGNEG
Soot%0.20.10.60.10.40.6
Fluid Condition
TBN7.912.5411.2113.1514.039.93
Viscosity8.28.99.19.910.110.3
Oxidation11.20(30)5.7(35.7)0(32.1)2.1(34.2)3.9(38.1)


I played with the exposure triangle to attempt to capture the sparkly flakes, but it's very hard to see them. I assure you they are there. You can see the piece of gasket material and some iron slivers.

IMG_0884.webp


Multiply the number of copper colored flakes you see here by 1000x.
IMG_0880.webp


IMG_0864.webp
 
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I know what that amount of metals looks like on a filter & in bright sunlight I can see all the metal in the oil...It isn't pretty to see. That Cu seemed to triple vs your 10k interval (93 & 289 ppm). Welp...time to trade it in... :ROFLMAO:
I'll assume you plan to do UOA on the 25'?
 
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Glad you caught it before it completely failed on you. I'm hoping this is a one off failure for the 3.0 Duramax and doesn't become common, its great driving powertrain. I haven't heard of a ton of problem with lower end failures on the 3.0L. Hopefully the 6.2L gives you less trouble than the 3.0L.
 
Stinks that was happening. I know you were a big fan of the economy from this powertrain.

Congrats on the new Tahoe. I think the LTs are sweethearts. Especially the little 5.3.
 
This is a perfect example of the power of UOAs. Relatively speaking, they are, by far, the least expensive means of measuring wear rates.

In many cases, UOAs simply show "normal" wear ongoing, and the "normalcy" of that wear is unable to distinguish variances of life's inputs (daily driving habits, temp changes in the environment, lube differences, etc). But in special circumstances, where wear rates are non-normal, even singular UOAs can detect impending conditions which are highly likely to end in a chronic catastrophic event. (Acute events will not be caught quickly due to the oil sample schedules, but those events are rarely predictable anyway, no matter the means.)

This also is an illustration of the need to understand the specific design, materials and construction of the equipment you own. Admittedly, I was misled initially based on my assumptions of the nature of this 3.0L Dmax relative to my experience and ownership of a 6.6L Dmax. Yet, those engines are as different as night and day. At first, the presumption was that Cu was coming from the oil cooler; a very prominent event in the larger engines. But as wwillson indicates, there is no similarity present in the smaller Dmax. There are but two sources of Cu and Tn in the LM2 engine; main bearings and con-rod bearings.

Finally, this also shows that no matter what oil you use, when a defect is present, there's no stopping the destruction. No Xw-40 grade would have prevented this. HPL (a top tier boutique lube) wasn't stopping this. The demise is imminent.


This is a real-life example of the concepts taught in this article; how UOAs should and should not be used as tools to understand wear.
https://bobistheoilguy.com/used-oil-analysis-how-to-decide-what-is-normal/
And this real life example saved wwillson from being caught stranded at roadside, hoping GM would not not only come to his rescue in the moment with a timely tow, but also relieve his mind rather than his wallet once that little engine screeched to a halt. And trust me, it's gonna die, sooner rather than later.
 
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This is a perfect example of the power of UOAs. Relatively speaking, they are, by far, the least expensive means of measuring wear rates.

In many cases, UOAs simply show "normal" wear ongoing, and the "normalcy" of that wear is unable to distinguish variances of life's inputs (daily driving habits, temp changes in the environment, lube differences, etc). But in special circumstances, where wear rates are non-normal, even singular UOAs can detect impending conditions which are highly likely to end in a chronic catastrophic event. (Acute events will not be caught quickly due to the oil sample schedules, but those events are rarely predictable anyway, no matter the means.)

This also is an illustration of the need to understand the specific design, materials and construction of the equipment you own. Admittedly, I was misled initially based on my assumptions of the nature of this 3.0L Dmax relative to my experience and ownership of a 6.6L Dmax. Yet, those engines are as different as night and day. At first, the presumption was that Cu was coming from the oil cooler; a very prominent event in the larger engines. But as wwillson indicates, there is no similarity present in the smaller Dmax. There are but two sources of Cu and Tn in the LM2 engine; main bearings and con-rod bearings.

Finally, this also shows that no matter what oil you use, when a defect is present, there's no stopping the destruction. No Xw-40 grade would have prevented this. HPL (a top tier boutique lube) wasn't stopping this. The demise is imminent.


This is a real-life example of the concepts taught in this article; how UOAs should and should not be used as tools to understand wear.
https://bobistheoilguy.com/used-oil-analysis-how-to-decide-what-is-normal/
And this real life example saved wwillson from being caught stranded at roadside, hoping GM would not not only come to his rescue in the moment with a timely tow, but also relieve his mind rather than his wallet once that little engine screeched to a halt. And trust me, it's gonna die, sooner rather than later.
I love everything you wrote, but you know two things:

A) Some other lube brands absolutely would have been blamed for this.
B) People will still use normal wear rate UOAs to compare motor oils


Great post!
 
Although it is obviously too much metal, it looks like metals per mile have stayed the same since about 13K. So this thing has had issues for a while.

Never thought I would see the day when a 0-20 oil was spec in a diesel.
 
Glad you caught it before it completely failed on you. I'm hoping this is a one off failure for the 3.0 Duramax and doesn't become common, its great driving powertrain. I haven't heard of a ton of problem with lower end failures on the 3.0L. Hopefully the 6.2L gives you less trouble than the 3.0L.
I had high hopes for that engine.
 
That is unfortunate, but at least you don't have to worry about it anymore! I was seriously considering this motor but the more I dug, the less intriguing it seemed. Not saying it's bad of course, just seems very hit and miss.

Best of luck with the new one!
 
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