2020 duramax 3.0 issues

[BeerCan]

I have a friend I visited last night that has a 2020 GMC PU with the 3.0 Duramax. He uses it to tow his camper and is having some serious issues with it.

3 x he has left on trips and has ended up having a no start issue. Truck runs fine, he turns it off and when he goes back it is completely dead, no crank, no dash lights just nothing. Goes to the dealer and of course they can't find the problem. He also has a tpms sensor issue they can't seem to find, dealer has replaced all tpms but truck keeps telling him he has a flat. In addition he has oil consumption issues, but he tells me that only happens when he tows said 1qt every 600 miles dealer of course said normal. Claims no consumption when not towing.

I told him to lemon it but he is stubborn and wants it fixed. I thought I would ask here if anyone has run into similar problems that they got resolved and what the eventual resolution was. He is not mechanically inclined so he would need to be coached on what to say to the dealer.

please lets not turn this into a bash GM thread, I just want to help this guy out because he spent good money on this truck and its failing him.

 

[Imp4]

I told him to lemon it but he is stubborn and wants it fixed. I thought I would ask here if anyone has run into similar problems that they got resolved and what the eventual resolution was. He is not mechanically inclined so he would need to be coached on what to say to the dealer.

please lets not turn this into a bash GM thread, I just want to help this guy out because he spent good money on this truck and its failing him

You can lead a horse to water but you cannot make him drink.
If your buddy is satisfied with working through his issues with the dealer, then there is likely not much you can do.
At the end of the day, you can provide him with your opinion but he needs to decide how to handle the issue at hand.

Cheers!!!

 

[Jetronic]

The tpms system needs to be coded to the correct air pressure depending on tyres fitted

The completely dead truck that cures itself points to a break inside the battery. Give the battery a couple whacks with the hand next time and if that revives it, replace...

What mileage on the engine and what oil is in it? Sometimes it just points to not yet run in engine, but sometimes the oil is too thin for the use the engine is seeing. If only consumption when towing, points to the latter

 

[wwillson]

In addition he has oil consumption issues, but he tells me that only happens when he tows said 1qt every 600 miles dealer of course said normal. Claims no consumption when not towing.

Does he know the oil temperature towing vs not towing? The GCWR is fairly low for the 1500 with the 3.0L Duramax, because they can't keep it cool with the low squat grill. Between the low cooling capacity and the ability of this engine to produce heat, I'll bet the oil temps are sky high. How much weight is he towing and at what ambient temperature?

 

[CKN]

I know a guy that has one and drives 50,000 miles a year-and thus far he loves his. No towing tho. However, even if the OP is over the numbers slightly he still shouldn't be seeing those issues.

 

[01rangerxl]

No crank / no lights conditions are often caused by problems with the distribution block on top of the battery (not specifically on the 3.0 Dmax, in general), but combined with TPMS problems, I wonder if something is wrong with the BCM (body control module). Of course that's assuming the TPMS is even set up correctly with the right tire size and everything. Your friend may need to try another dealer if they are just throwing sensors at it and not actually diagnosing anything.

As for the oil consumption, I don't know. Rear main seals have been an issue on 3.0 Dmaxes, but that would be a pretty noticeable leak that is present all of the time.

 

[MNTIM]

Does he know the oil temperature towing vs not towing? The GCWR is fairly low for the 1500 with the 3.0L Duramax, because they can't keep it cool with the low squat grill. Between the low cooling capacity and the ability of this engine to produce heat, I'll bet the oil temps are sky high. How much weight is he towing and at what ambient temperature?

So how these trucks manage temps is really interesting to watch. They will all run 230 on the oil Temps on the freeway. Once the oil hits 212 they kick up Coolant temp until oil
Temp gets to 230 and then the coolant goes back down to 212. So when you see videos or picture of peoples coolant gauge reading high it’s because the truck is using coolant to heat the oil to 230.
When working they can drop coolant temps to 190 even when working very hard to cool oil down but I’ve never seen it get hot enough to do that. General towing freeway I’ll see 240-250.
There were a handful of trucks out of the door that had some pvc issues and that’s where the loss of oil was coming from. But me and many others have no issues. super happy.
They all Do use a new 0w20 which they call dexos D spec. Only 3 choices
Ac delco 0w20 dexos d
M1 0w20 esp
Amsoil 0w20 dexos d spec