Thoughts on purchasing a higher-mileage Duramax?

Seamus said:

We have a diesel Guru tech at our GMC. Great guy, has said most all you mentioned. The oil consumption is a baffle in the valve cover. They replace the valve cover. Only effects 20-21's . . . . .now and charge more for it. Its not fun anymore, its offensive. I can buy anything i want, but i won't. 85K for a GM truck...its crazy. A Mercedes GLS is 97K and very luxurious and high quality. Yes they have issues as all trucks do. At 100K I'll be out of warranty and fix what breaks.

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CTown Duramax said:

Do you know where I can find the relevant VIN ranges?

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Seamus said:

We have a diesel Guru tech at our GMC. Great guy, has said most all you mentioned. The oil consumption is a baffle in the valve cover. They replace the valve cover. Only effects 20-21's within a certain vin code. Coolant valve is a complex piece which was bound to be a problem...and it is. Still not a reason to get a new truck. There will be a new improved version at some point no doubt. Our guru who isnt a fan of this motor said they dont blow up. He has only replaced one 3.0 motor. Bad from factory according to him. I have a 2021 3.0 w/ 42K on her in perfect condition. I have only had a leaking radiator a quality control issue he said. They crack and leak on a weld. I just had this conversation with him as I want to go the distance with this truck. He has heard of the timing chain stretch and has not seen one yet. Mind you other dealers and customers travel to have him work on their diesels. Sees alot of trucks. As far as GM trucks go the 3.0 is about the best out there. I know people are programmed to fear being out of warranty, but it cheaper to fix a 3.0 than by a new GM truck today. I am prepared to pay at some point but know its cheaper than doubling down on a new GM truck. A Yukon Denali XL is 85K!! I dont care if something is 5K or 8K to change a Timing chain. He said its about 40 hours at 175 an hour thats still 7K. Much cheaper than getting killed on a trade and paying 85K to start a new story. I used to need a small reason to get a new truck every few years....But GM changed that. They make crap now and charge more for it. Its not fun anymore, its offensive. I can buy anything i want, but i won't. 85K for a GM truck...its crazy. A Mercedes GLS is 97K and very luxurious and high quality. Yes they have issues as all trucks do. At 100K I'll be out of warranty and fix what breaks.

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TiGrayMSM said:

My take as fellow 3.0 owner (2022 Yukon XL) is to buy the newest model year you can, especially for the LM2 diesels (2021-2024 for the SUVs). The early LM2s do have issues, which I have confirmed after befriending the diesel mechanic at our dealership. Areas to look out for per the tech:

1. Early builds (2020-2021) are prone to oil leaks (rear main)
2. Early build LM2s are starting to come in for timing issues caused by timing chain stretch. This is a massive cab-off job. The tech said GM updated the chains with a new design in 2022 (maybe earlier?)
3. Oil consumption (there is a TSB for this, involves replacing the camshaft housing. Also early builds)
4. Coolant control valve. He has seen both LM2 and LZ0s coming in with this issue, but especially higher mileage LM2.

Per the technician, almost everything involving the LM2s is very labor intensive so he is wary of owning one outside warranty.

With about 70k on our 2022 now, this is what has been replaced that is diesel specific: All replaced under warranty (some of it covered by CPO warranty):

1. NOx sensor
2. DEF sensor recalibration (the gauge was wildly inaccurate when towing. The update has helped somewhat)
3. Oil consumption (heavy consumption for us when towing). We had the oil consumption TSB performed and so far results are excellent. But FYI, this job was billed at 18 hours!
4. EGR valve replacement and EGR cooler replacement due to coolant leaks.
5. Coolant control valve replacement (P1098)
6. Intercooler replacement (massive internal coolant leak)

On the plus side, doing a transmission fluid/filter change is much easier on the diesels. The gassers have a crossover pipe right under the pan. I was intending to keep the Yukon long term.... as we do for all our cars. However, in this case, I will make the decision when we are closer to 100k.

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dbphillips said:

Geez, is yours an early or late 2022 build?

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