5w-30

[GSPHerder]

So now the engineers who designed, tested, and validated the engine are just “bean counters”… but a few random forum posts and oil analyses are the gold standard?

What else would you call those jackasses that put in plastic oil pans on a offroad truck, hoods that are so thin they rattle down the hwy, jackasses that say stupid stuff like lifetime trans oil, 10k oil changes.

I suppose we could call them "dennisd"

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[32spoke]

So now the engineers who designed, tested, and validated the engine are just “bean counters”… but a few random forum posts and oil analyses are the gold standard?


That’s backwards.


Toyota didn’t land on 0W-20 by guessing or chasing spreadsheets—they validated it through full-system testing: flow characteristics, wear rates, temperature control, cold-start performance, and long-term durability.


Meanwhile, what’s being presented here? A couple pressure readings and scattered UOAs with zero control variables. That’s not proof—that’s anecdote.


Matching pressure doesn’t mean matching lubrication, and it definitely doesn’t mean better protection.


If thicker oil were actually superior in this engine, you wouldn’t need forum threads to prove it—you’d see spec changes, TSBs, and warranty data reflecting it. That’s how real evidence shows up.

Oil spec for El Paso, Texas- 0w20
Yet just across the border in another North American country, Mexico, like Jaurez.. 5w30/10w30. Same climate as El Paso

 

[DENNISD]

Oil spec for El Paso, Texas- 0w20
Yet just across the border in another North American country, Mexico, like Jaurez.. 5w30/10w30. Same climate as El Paso

That argument sounds good on the surface, but it doesn’t actually prove what you think it does.


Specs aren’t set by geography alone. They’re driven by emissions requirements, fuel economy regulations, fuel quality, and maintenance assumptions. The U.S. spec leans heavily on fuel economy and emissions compliance—hence 0W-20.


Mexico using 5W-30 doesn’t suddenly mean thicker oil is “better”—it means they’re operating under a different set of constraints.


If thicker oil was objectively superior for this engine, Toyota wouldn’t quietly limit it to certain regions—you’d see a global spec change. You don’t.

 

[DENNISD]

What else would you call those jackasses that put in plastic oil pans on a offroad truck, hoods that are so thin they rattle down the hwy, jackasses that say stupid stuff like lifetime trans oil, 10k oil changes.

I suppose we could call them "dennisd"

Got it—so we’ve moved from “data” to just calling engineers jackasses.


Pointing at plastic oil pans and rattling hoods has nothing to do with oil viscosity requirements. That’s just deflection.


You still haven’t shown anything that outweighs manufacturer-level testing—just opinions and scattered forum data.

 

[32spoke]

That argument sounds good on the surface, but it doesn’t actually prove what you think it does.


Specs aren’t set by geography alone. They’re driven by emissions requirements, fuel economy regulations, fuel quality, and maintenance assumptions. The U.S. spec leans heavily on fuel economy and emissions compliance—hence 0W-20.


Mexico using 5W-30 doesn’t suddenly mean thicker oil is “better”—it means they’re operating under a different set of constraints.


If thicker oil was objectively superior for this engine, Toyota wouldn’t quietly limit it to certain regions—you’d see a global spec change. You don’t.

Now you just agreed with me? . I have been writing about the CAFE requirements driving oil viscosities to be lowered for this engine, as indicated by owner Manuals from other countries.

GM switched from 0W20 to 0w40 for their 6.2 engines that had crankshaft/main cap issues. After verifying which engines were not making audible noise, in the “at risk” run of engines, GM swapped the oil viscosity from 0w20 to 0w8… oh, meant 0w40 mobil1 super car oil that was designed for their C8 engines…

 

[BLtheP]

For him calling Toyota’s engineers “bean counters” while leaning on random forum oil analyses and pressure screenshots is a pretty low bar for evidence.


Matching pressure doesn’t equal protection, and a few UOAs don’t prove anything beyond isolated results.


That’s not science—that’s confirmation bias.

So now the engineers who designed, tested, and validated the engine are just “bean counters”… but a few random forum posts and oil analyses are the gold standard?


That’s backwards.


Toyota didn’t land on 0W-20 by guessing or chasing spreadsheets—they validated it through full-system testing: flow characteristics, wear rates, temperature control, cold-start performance, and long-term durability.


Meanwhile, what’s being presented here? A couple pressure readings and scattered UOAs with zero control variables. That’s not proof—that’s anecdote.


Matching pressure doesn’t mean matching lubrication, and it definitely doesn’t mean better protection.


If thicker oil were actually superior in this engine, you wouldn’t need forum threads to prove it—you’d see spec changes, TSBs, and warranty data reflecting it. That’s how real evidence shows up.

That argument sounds good on the surface, but it doesn’t actually prove what you think it does.


Specs aren’t set by geography alone. They’re driven by emissions requirements, fuel economy regulations, fuel quality, and maintenance assumptions. The U.S. spec leans heavily on fuel economy and emissions compliance—hence 0W-20.


Mexico using 5W-30 doesn’t suddenly mean thicker oil is “better”—it means they’re operating under a different set of constraints.


If thicker oil was objectively superior for this engine, Toyota wouldn’t quietly limit it to certain regions—you’d see a global spec change. You don’t.

You keep repeating “Toyota tested it” like that settles the discussion, but it doesn’t.

Testing only proves it met a set of targets. It doesn’t prove it’s the best possible choice for the engine independent of those targets.

Manufacturers are balancing emissions, fuel economy regulations, warranty risk, and cost. So when 0W-20 gets approved, that means it checked all those boxes—not that it maximizes mechanical margin or long-term wear protection.

The regional specs are the giveaway. If 0W-20 were objectively optimal for the engine itself, you wouldn’t see thicker oil specified anywhere. The fact that you do means viscosity is being adjusted based on external constraints, not just engine design.

That’s the part your argument keeps avoiding.

Got it—so we’ve moved from “data” to just calling engineers jackasses.


Pointing at plastic oil pans and rattling hoods has nothing to do with oil viscosity requirements. That’s just deflection.


You still haven’t shown anything that outweighs manufacturer-level testing—just opinions and scattered forum data.

You still haven’t actually engaged with the argument—you’re just repeating the same talking point and ignoring the parts that don’t fit it.

There may very well be tradeoffs here—that’s the entire point of the discussion—but you haven’t identified a single one from a mechanical standpoint. The only thing you’ve pointed to is warranty and “Toyota tested it,” which doesn’t address how viscosity impacts wear, film strength, or temperature margins in real-world operation.

Simply repeating “Toyota tested it” isn’t an argument, and continuing to fall back on it doesn’t move the discussion forward.

 

[DENNISD]

You keep repeating “Toyota tested it” like that settles the discussion, but it doesn’t.

Testing only proves it met a set of targets. It doesn’t prove it’s the best possible choice for the engine independent of those targets.

Manufacturers are balancing emissions, fuel economy regulations, warranty risk, and cost. So when 0W-20 gets approved, that means it checked all those boxes—not that it maximizes mechanical margin or long-term wear protection.

The regional specs are the giveaway. If 0W-20 were objectively optimal for the engine itself, you wouldn’t see thicker oil specified anywhere. The fact that you do means viscosity is being adjusted based on external constraints, not just engine design.

That’s the part your argument keeps avoiding.





You still haven’t actually engaged with the argument—you’re just repeating the same talking point and ignoring the parts that don’t fit it.

There may very well be tradeoffs here—that’s the entire point of the discussion—but you haven’t identified a single one from a mechanical standpoint. The only thing you’ve pointed to is warranty and “Toyota tested it,” which doesn’t address how viscosity impacts wear, film strength, or temperature margins in real-world operation.

Simply repeating “Toyota tested it” isn’t an argument, and continuing to fall back on it doesn’t move the discussion forward.

You’re right about one thing—there are tradeoffs. That’s exactly why this isn’t as simple as “thicker = better.”


What you’re still not showing is any mechanical evidence that moving to a thicker oil actually improves outcomes in this engine. Not theory—actual controlled data.


You keep saying 0W-20 just “meets targets,” but those targets include wear, durability, and protection. Toyota doesn’t separate “passes emissions” from “engine survives long-term”—those are validated together.


And on the regional spec point—you’re assuming different viscosity automatically means one is mechanically superior. It doesn’t. It means the acceptable operating window is broad enough that multiple viscosities can meet minimum requirements under different constraints.


That’s not proof that 5W-30 improves wear—it’s proof the engine can tolerate it.


Where your argument falls apart is the leap from:
“Different specs exist” → “Thicker oil provides better protection.”


That step requires evidence—and that’s the part that’s missing.


Right now, the only “support” being offered is:

• Pressure readings (which don’t measure film thickness or wear)
• UOAs (which are highly variable and not controlled)

That’s not enough to override a validated spec.


If thicker oil actually delivered measurably better wear protection in this engine, you wouldn’t need to infer it from regional charts and forum data—you’d see it clearly in controlled testing, fleet data, or spec revisions.


Until then, calling it “better” isn’t engineering—it’s assumption.

 

[DENNISD]

Now you just agreed with me? . I have been writing about the CAFE requirements driving oil viscosities to be lowered for this engine, as indicated by owner Manuals from other countries.

GM switched from 0W20 to 0w40 for their 6.2 engines that had crankshaft/main cap issues. After verifying which engines were not making audible noise, in the “at risk” run of engines, GM swapped the oil viscosity from 0w20 to 0w8… oh, meant 0w40 mobil1 super car oil that was designed for their C8 engines…

Not really—I didn’t agree with your conclusion, just the existence of tradeoffs. You’re still making a leap you haven’t supported.


Yes, regulations like CAFE can influence viscosity targets. That’s not controversial. What you haven’t shown is that those targets come at the expense of durability in this engine.


“Driven by regulations” ≠ “compromised protection.”


On the GM example—you’re comparing a known failure case to a platform where no such pattern exists. GM didn’t change viscosity because thicker oil is universally better—they changed it because there was a specific, documented mechanical issue.


That actually reinforces my point:
When viscosity is insufficient, you see failures, TSBs, spec updates, and corrective action.


Where is that for this engine on 0W-20?


Because without that, you’re not demonstrating that 0W-20 is inadequate—you’re just pointing out that thicker oil exists and assuming it’s better.


And that’s the gap in your argument

 

[maxx075]

 

[DENNISD]

When the data runs out, the memes show up.


Still haven’t seen anything that demonstrates thicker oil improves wear or durability—just jokes and assumptions.

 

[Will721]

Viscosity aside, the more I think about it the more uncomfortable I feel about the idea of an electronically controlled oil pump. Anyone else? Mabey I'm just getting older and heading towards that new technology bad mindset. Frankly I'm just following this thread for the laughs at this juncture. But every time someone brings up that variable displacement pump the thought just grinds in the back of my mind.

What if the oil pressure sensor fails? Its not that uncommon of an issue in the automotive world. Typically when it happens it throws a code or just reads incorrectly on a guage. Swap the sensor for $40 and there's no harm or fowl. But the idea that now it could fail, and cause the engine to run low on oil pressure just makes me paranoid. Especially because you'd never even know it was happening before it would be too late. Oil pumps have always been a simple part that almost never fails, the addition of electronic control and variable flow also seems like it would cause a higher failure rate as well. Probably just paranoid for nothing. But if the aftermarket stepped in with a conventional option I'd definitely consider it.

 

[BLtheP]

Viscosity aside, the more I think about it the more uncomfortable I feel about the idea of an electronically controlled oil pump. Anyone else? Mabey I'm just getting older and heading towards that new technology bad mindset. Frankly I'm just following this thread for the laughs at this juncture. But every time someone brings up that variable displacement pump the thought just grinds in the back of my mind.

What if the oil pressure sensor fails? Its not that uncommon of an issue in the automotive world. Typically when it happens it throws a code or just reads incorrectly on a guage. Swap the sensor for $40 and there's no harm or fowl. But the idea that now it could fail, and cause the engine to run low on oil pressure just makes me paranoid. Especially because you'd never even know it was happening before it would be too late. Oil pumps have always been a simple part that almost never fails, the addition of electronic control and variable flow also seems like it would cause a higher failure rate as well. Probably just paranoid for nothing. But if the aftermarket stepped in with a conventional option I'd definitely consider it.

I certainly don’t love it, but I don’t know what you can do about it. I haven’t looked into it but I imagine there is a fail safe built in to some extent. Maybe the solenoid or part that “opens up” to reduce pressure is spring loaded so that if controls failed, it would default to the higher pressure mode? Not sure, I can check the FSM later to see if it talks about function and failures and not just replacement instructions.

 

[BLtheP]

You’re right about one thing—there are tradeoffs. That’s exactly why this isn’t as simple as “thicker = better.”


What you’re still not showing is any mechanical evidence that moving to a thicker oil actually improves outcomes in this engine. Not theory—actual controlled data.


You keep saying 0W-20 just “meets targets,” but those targets include wear, durability, and protection. Toyota doesn’t separate “passes emissions” from “engine survives long-term”—those are validated together.


And on the regional spec point—you’re assuming different viscosity automatically means one is mechanically superior. It doesn’t. It means the acceptable operating window is broad enough that multiple viscosities can meet minimum requirements under different constraints.


That’s not proof that 5W-30 improves wear—it’s proof the engine can tolerate it.


Where your argument falls apart is the leap from:
“Different specs exist” → “Thicker oil provides better protection.”


That step requires evidence—and that’s the part that’s missing.


Right now, the only “support” being offered is:

• Pressure readings (which don’t measure film thickness or wear)
• UOAs (which are highly variable and not controlled)

That’s not enough to override a validated spec.


If thicker oil actually delivered measurably better wear protection in this engine, you wouldn’t need to infer it from regional charts and forum data—you’d see it clearly in controlled testing, fleet data, or spec revisions.


Until then, calling it “better” isn’t engineering—it’s assumption.

For someone asking everyone else for evidence, it’s interesting you haven’t provided a single mechanical explanation for your own position.

Why not find another thread to interact with? You’re not contributing anything here and are just repeating the same generic points while burying the actual discussion. You clearly have no interest in the topic this thread is about. This thread is not about the owner’s manual.

 

[DENNISD]

For someone asking everyone else for evidence, it’s interesting you haven’t provided a single mechanical explanation for your own position.

Why not find another thread to interact with? You’re not contributing anything here and are just repeating the same generic points while burying the actual discussion. You clearly have no interest in the topic this thread is about. This thread is not about the owner’s manual.

Asking for evidence isn’t the problem—being unable to provide it is.

 

[BLtheP]

Asking for evidence isn’t the problem—being unable to provide it is.

That’s exactly the problem: you’re not holding yourself to the same standard. You keep demanding technical proof from everyone else while providing none yourself. So go ahead - show the real technical data proving the owner’s manual recommendation is mechanically superior. I’ll wait.

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