[Ryephile]

Originally Posted by Mr. Wyndham

...But to discount their expertise and recommendations isn't the wisest thing I've ever heard of.

Read more carefully. I asked "why". Nowhere did I discount their recommendations. Everything from 0W-20 to 15W-50 is "recommended" depending on the context, all with the same bearings and oil system.

[Mr. Wyndham]

Originally Posted by Ryephile

Read more carefully. I asked "why". Nowhere did I discount their recommendations. Everything from 0W-20 to 15W-50 is "recommended" depending on the context, all with the same bearings and oil system.

I realize that, it was more of a hypothetical statement.

While 0W20 may be used in some applications, nowhere in the 2010-2018 Camaro owners manual does it list 0-20 as a recommended oil. The closest you'll find is 0W30, for those who drive in persistently frigid temperatures. So that, to me...rules it out.

We just don't know enough to make the assumption that everything is fair game. Will your engine seize or blow up? Probably not...I just choose to adhere to the written recommendations while operating within factory spec as best I can. I buy Delco oil filters, etc...Most of that motivation comes from discussions with the quality and warranty people. A few stories were enough to display quite clearly they knew more than we do, or at least me.

[CruzySS]

Trust me engineers aren't as smart as they think they are. Just hide behind the job title. Most are no more qualified than me or you.

[Mr. Wyndham]

I respectfully disagree in this case.

[Norm Peterson]

Originally Posted by CruzySS

Trust me engineers aren't as smart as they think they are. Just hide behind the job title. Most are no more qualified than me or you.

I guess it's easier to bash something you don't understand than try to understand it. Or, in this instance, the thought process itself.


So far, we have just two datapoints here, trucks and a performance car. Seems like a good enough clue all by itself to expect slightly different oil recommendations. Or at least not be surprised when they aren't the same.


Norm

[Ryephile]

I'm glad Norm brought that up.

*Heavy truck with big aero drag, towing thousands of pounds = lower viscosity oil
*Much lighter low aero drag car, no towing = higher viscosity oil

Wait, that's backwards. Could it be the variable displacement oil pump is able to handle the bandwidth of viscosities? The ECU does have Oil pressure minimum's vs. RPM that will throw a CEL. As such a too-low viscosity oil (or a broken-down dino-oil) beyond the scope of the oil pumps adjustability increases the probability of triggering a CEL.

[Norm Peterson]

Maybe the trucks aren't expected to be run up to or past 6000 rpm?


Norm

[Ryephile]

Originally Posted by CruzySS

Trust me engineers aren't as smart as they think they are. Just hide behind the job title. Most are no more qualified than me or you.

That kind of blanket statement is unacceptable, and discounts all the educated and experienced Engineers that are competent. Your assertion is akin to saying "the Earth is flat" because you choose to not abide by the scientific process.

Are you able to calculate the Reynolds equations for hydrodynamic bearings?

[Ryephile]

Originally Posted by Norm Peterson

Maybe the trucks aren't expected to be run up to or past 6000 rpm?

The LT1 and L86 do have different RPM limits as a result of their different intake manifold designs. 5800 vs 6500. RPM alone is meaningless. The "get to the end" part is, what is the oils' viscosity at its operating temperature? That is what matters to the end user.

[Mr. Wyndham]

In the truck's manual:

Use SAE 0W-20 viscosity grade for the 5.3L and 6.2L V8 engines. Use SAE 5W-30 viscosity grade for the 4.3L V6, and 6.0L V8 engines.

Cold Temperature Operation: In an area of extreme cold, where the temperature falls below 29 °C (20 °F), an SAE 0W-30 oil may be used in the 4.3L or 6.0L engine. An oil of this viscosity grade will provide easier cold starting for the engine at
extremely low temperatures.

Something is different between these engines. I have no idea what...but something is. If the reason for 0W20 was strictly for fuel economy, they'd have been more likely to use it across the board, but they didn't.

[Ryephile]

Originally Posted by Mr. Wyndham

...Something is different between these engines. I have no idea what...but something is. If the reason for 0W20 was strictly for fuel economy, they'd have been more likely to use it across the board, but they didn't.

But they did, according to my UOA, which was an xW-20 from the factory.

One probability is all the factory fills are now 0W-20 for exactly that reason, fuel economy, and they just didn't make that public information. Until more people do factory fill UOA's, we only have my data point.

The performance supplement already says to change to an xW-40 Dexos 2 for track use, so that rules out having a 0W-20 on the track and the oil pressure being too low at 270°F oil temps.


I think a takeaway here is, the general public aren't always privy to OEM information, even if you do have a "friend" inside.

[Mr. Wyndham]

Ok...

[Norm Peterson]

Could the xW20 be formulated with the initial 1500-mile break-in period in mind, after which the OM & maintenance documentation would take over?


Norm

[CruzySS]

That's funny! Well I'm an engineer and said the statement since it's true. Look at the A8 transmission and the torque converter. That was an engineering failure. How about the HVAC system fogging up the windshield. Another engineering failure. So these must be the competent people you are talking about?