2021 GMC Yukon Denali Oil Burn

[DontTaseMeBro]

If I were in your shoes (collectively), I would stop using that piss water equivalent of 0w-20 oil and put in 5w-30. 0w-20 is a CAFE gimmick to eeeekkkkkk out a minute amount of mpg on EPA testing.

Run an oil designed for heavier use. 5w-30 has been the staple since around 2000, so why change now? The 6.6L gas motor specifies 5w-30 right on the oil cap. They share a lot of the same architecture, I'd go with what a commercial vehicle uses. Just my opinion.

What I wanna know is, how does 0W-20 wear compared to 5W-30 or 5W-40. Conventional wisdom would say it wears the same which isn’t a good thing. But ya, I’d still would wanna know.

 

[Antonm]

What I wanna know is, how does 0W-20 wear compared to 5W-30 or 5W-40. Conventional wisdom would say it wears the same which isn’t a good thing. But ya, I’d still would wanna know.

Conventional wisdom absolutely does not say it wears the same. Viscosity is key to preventing metal on metal wear.

The argument here between the oils would be does the 0w20 have enough viscosity,,,if it does,,, then there would be no benefit to thicker oils. And if the 0w20 did have enough viscosity, the downside of running a thicker oil would be a slight reduction in HP and fuel economy.

On the flip side, if the 0w20 doesn’t have enough viscosity to maintain the oil wedge between components, then the thicker oils would greatly reduce wear/ extend engine life.
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[15burban]

I've seen uoa's people have posted switching back and forth between 0w20 and 5-30. Same oci and the 0w20 show more wear. Does that mean that same motor will "wear out" 5k miles earlier running 0w20 or 50k? I don't know. If you trade in every few years does it really matter. We keep our vehicles for as long as possible so the only thing I ever put 0w20 in was the wife's last little mitsubishi suv that had a lifetime power train warranty.

 

[DontTaseMeBro]

Conventional wisdom absolutely does not say it wears the same. Viscosity is key to preventing metal on metal wear.

The argument here between the oils would be does the 0w20 have enough viscosity,,,if it does,,, then there would be no benefit to thicker oils. And if the 0w20 did have enough viscosity, the downside of running a thicker oil would be a slight reduction in HP and fuel economy.

On the flip side, if the 0w20 doesn’t have enough viscosity to maintain the oil wedge between components, then the thicker oils would greatly reduce wear/ extend engine life.
…

What I meant by “wears the same” is the time it takes(engine hours) to wear down from its 20 viscosity. There’s a post in one of the other threads where it’s states that after 3000 miles driven, 5w-40 was barely at that viscosity still.

So to restate what I was saying, would 0w-20 still have a viscosity of 20 after 3000 miles?

 

[Antonm]

What I meant by “wears the same” is the time it takes(engine hours) to wear down from its 20 viscosity. There’s a post in one of the other threads where it’s states that after 3000 miles driven, 5w-40 was barely at that viscosity still.

So to restate what I was saying, would 0w-20 still have a viscosity of 20 after 3000 miles?

Ah, you were talking about shear reducing viscosity of oil over time.
Of course both oils will shear as they're used, but they probably won't shear at the same rate. Generally the higher the spread between the winter number (the "0" in 0W40) and normal viscosity number (the "40" in 0W40) means the oil will shear quicker (i.e a 0W40 will shear quicker than a 15W40) .
This used to be a big concern for the diesel guys that like to really extend oil change intervals, but it's been talked about less in recent years so maybe it's not as big a deal as it once was.
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[DontTaseMeBro]

Ah, you were talking about shear reducing viscosity of oil over time.
Of course both oils will shear as they're used, but they probably won't shear at the same rate. Generally the higher the spread between the winter number (the "0" in 0W40) and normal viscosity number (the "40" in 0W40) means the oil will shear quicker (i.e a 0W40 will shear quicker than a 15W40) .
This used to be a big concern for the diesel guys that like to really extend oil change intervals, but it's been talked about less in recent years so maybe it's not as big a deal as it once was.
...

That’s exactly what I meant, thank you! So yes, would be interesting to see how 0W-20 shears in the real world compared to the other viscosity oils.

 

[geneblakeney]

I have a 21 Yukon. I had this same issue. Low oil warning. I checked dipstik. It was very low. It persisted. Finally took it to the shop at 101k miles. OUT of warranty. They said the gaskets on the pistons deteriorate and that causes oil to leak in there and burn up. Only fix is to rebuild engine or replace. They said it also has a little bit of oil leak. No one said anything about type of oil used. They said that i just need to change oil every 4-5k miles. Ignore what computer says. It will extend the oil life based on highway miles. All that being said we will probably buy a new one soon.