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

[dnewton3]

A) Some other lube brands absolutely would have been blamed for this.

Sadly true. Totally wrong to do so, but that doesn't stop folks.

B) People will still use normal wear rate UOAs to compare motor oils

Again, true. And again, totally wrong to do so, but that doesn't stop folks.



All we can do is continue to dispel the inaccurate myths and prevalent rhetoric of the uneducated.

 

[twX]

After your last post, I suspected that the problem could be turbo bearing wear.

One thing I missed was the high silver on the first two UOAs, which totalled 11 ppm over the first 10k miles. It's very likely that the rod and/or main bearings have silver-based overlays. The universal average for silver is 1 ppm. After 10k miles, the silver settled down, while copper and tin shot up, since one or more bearings were getting worn through to the bronze layer.

11 ppm of bearing material in the first 10k miles while the engine is breaking in might not seem like it should set off red flags, but a single rod bearing will tend to only contain something like 50 to 100 ppm worth of material in the overlay. The wear is usually concentrated on a small portion of the bearing as well. High wear rates also tend to produce larger wear particles that can get caught in the oil filter and won't show up on a UOA.

Even the 6 ppm silver on the first UOA at 3k miles could have been interpreted as a warning flag, assuming that silver rarely reads any higher than 1 or 2 ppm on the factory fill.

 

[Zee09]

Yes, the manufacturing problem with the 6.2L cranks was solved after a manufacture data of June 1, 2024. However, this is way OT.

Did you work a fair deal ???

 

[USask2000]

I wonder how the dealership will proceed knowing that they took a vehicle on trade with an engine on its way out?

 

[wwillson]

Did you work a fair deal ???

Fair yes, inexpensive no.

 

[JustinH]

Hope the next guy of the Chevy certified preowned buys the long additional warranty.

You did the right thing in dumping it.

 

[Zee09]

Have you given up on diesels Wayne. I like them but went back to gas since 2015 but miss the diesel resale value on Fords.

 

[wwillson]

Have you given up on diesels Wayne. I like them but went back to gas since 2015 but miss the diesel resale value on Fords.

I still have the 6.6L Duramax in the truck. Pulling a 20k trailer pretty much requires a diesel, so no I haven't given up.

I went back to a gas motor in the Tahoe because I didn't love the complexity of the emissions system in the 3.0L. The more I learned about it and operated it, the more I believe the emissions system would require very expensive maintenance long before I got to 10 years and 250k miles. Almost all of the emissions system is packed into the engine bay. If you need to replace the DPF, it requires so much labor to disassemble pretty much everything on that side of the engine, people are paying $6-10k. If you look at the engine bay of the gas V8 it practically looks empty in comparison.

The 3.0L gets 29.5 MPG on the highway vs. 20 MPG for the 6.2L, but over time you don't save anything with the diesel.

 

[KEVINK0000]

Amazing. Thanks for posting. Incredible how many bottom end issues in the last decade on new designs across so many makes.

 

[4WD]

I hope your right about the 6.2! My research indicated otherwise. Typically gm junk

What research is that?

 

[bioilcurious]

What research is that?

According to gm from this article https://gmauthority.com/blog/2025/0...all-doesnt-apply-to-2025-model-year-vehicles/ . "A series of crankshaft and connecting rod manufacturing improvements implemented on or before June 1st, 2024, addressed contamination and quality issues. Model-year 2025 vehicles were built after these improvements and are not included in the recall."
Also, the 2019 and 2020 6.2L engines were excluded from the recall, as they claim those motors were not affected by the manufacturing defects. All signs point to @wwillson not having a catastrophic failure of his motor.

My "research" is unverified and consists of anecdotal posts from various GM forums. Some people have reported engine failures in MY2025 6.2L vehicles, along with a whole host of other problems ranging from limp modes to transmission issues to electrical issues. The list goes on.

In GM we trust

 

[4WD]

According to gm from this article https://gmauthority.com/blog/2025/0...all-doesnt-apply-to-2025-model-year-vehicles/ . "A series of crankshaft and connecting rod manufacturing improvements implemented on or before June 1st, 2024, addressed contamination and quality issues. Model-year 2025 vehicles were built after these improvements and are not included in the recall."
Also, the 2019 and 2020 6.2L engines were excluded from the recall, as they claim those motors were not affected by the manufacturing defects. All signs point to @wwillson not having a catastrophic failure of his motor.

My "research" is unverified and consists of anecdotal posts from various GM forums. Some people have reported engine failures in MY2025 6.2L vehicles, along with a whole host of other problems ranging from limp modes to transmission issues to electrical issues. The list goes on.

In GM we trust

As I posted before - my friend has a late year 2024 ZR2 Bison - and the dealership cleared his 6.2 - changed the oil 0W20 for 0W20 … He headed for the trails and beat on it all day long …
Obviously Wayne felt the problem was isolated bcs I know what those units sell for.
Since you have done such extensive research - do tell what percentage of these motors produced - were of this vintage with crank issues …