Why is it NOT OK for 0w40 in GM 5.3 engine?

[4wd]

I have a 2024 Sierra 5.3 with a Carbyte dfm disabler and I’m using Mobil 1 FS 0w40 and a Mobil 1 oil filter.
I opted for the 0w40 to hopefully protect the lifter assembly, though I’m not sure anything will help, and I’m not a believer in 0w20 oil. My theory is that since the valve/lifter assembly is the same as the 6.2, since GM is using 0w40 in it, then it should be good for the 5.3.
Anyway, folks have told me that I’m wearing out the oil pump, the lifter oil holes are too small, and the overall drag on the engine will cause premature wear.
Also, my gas mileage will be abysmal…but I’m getting 21+ mpg on the hiway at 78-80 mph, and the same 16-17 mpg around town.
So, I thought I’d ask you experts!! Should I stay with the 0w40 or back down to 0w30 or 5w30? Those are the recommendations I’ve received, as well as returning to the water like 0w20. Any advice is appreciated

How did you land on the Carbyte instead of Range ?

 

[TimeFlies]

You're using a great oil, keep doing so.

And whomever told you that its wearing out your oil pump, never listen to anything that person ever says again.

 

[ZeeOSix]

Anyway, folks have told me that I’m wearing out the oil pump, the lifter oil holes are too small, and the overall drag on the engine will cause premature wear.

Where are these folks getting their technical tribology information? Maybe they should try some 0W-5 racing oil will help their engines even more if they believe what they claim.

 

[ZeeOSix]

But a few mechanics and service folks said I was wrong.

It's amazing how many people in the auto industry don't understand the basics of Tribology, or even how an engine oiling system and journal bearings work, or understands multi-viscosity oil including what the W rating means and how it's determined.

 

[TimeFlies]

Where are these folks getting their technical tribology information? Maybe they should try some 0W-5 racing oil will help their engines even more if they believe what they claim.

Some -50W0 race blend, will flow instantly upon engine start, even at -70, and garner you an extra 65 mpg, due to low pumping effort.

 

[zogg]

I opted for the Carbyte over the range primarily because the range requires removing part of the inner wheel and plugging it into the computer harness. Not a hard job but a pain if I have to remove it to take it in to the dealer. The Carbyte just plugs into the obd port. After I bought it I realized it was $150 cheaper than the range. Hurrah.
It had excellent reviews like the range, though not as many. Some folks say you have to drive over 40 mph to activate. That’s true but it’s only ONE TIME TO WAKE IT UP. Then is always active at any speed.