We finally got some... 0W-8.

[ekpolk]

The bottom line is that Toyota engineers understand Tribology and know thicker oils provide more engine protection with more demanding engine use, and they don't even put a viscosity limit on how thick an owner could decide to use based on their OM statement. The reason they say to change it back to 0W-8 at the next oil change is because they used 0W-8 to qualify it for CAFE credits and part of CAFE requirements is they must "recommend" and push the use of that recommended oil viscosity - also the reason it's also printed on the oil filler cap.

Respectfully, you’re assuming a bit too much. Are not both cold starts, and the frequent on-off cycling of hybrid engines also “demanding” engine uses? As for the weasel words about going back to 0w-8 after using a thick 16, don’t forget, there can be, and very frequently are, multiple reasons or motivations behind a particular decision. Sure, that approach allows them to tell regulators, “see, we’re encouraging customers to use the lower vis oils.” But at the same time, you we simply cannot rule out the possibility that the characteristics of the 0w-8 oil actually do as good, or even a better job of lubricating this engine during the operations it’s going to see during 95+% of its life.

A point to consider: I keep a ScanGauge-III hooked up to my OBD port at all times. One of the parameters I keep displayed on the Home screen is OIL TEMPERATURE. In normal around town driving, the highest temps I’ll see are around 180F. The highest I’ve thus far been able to produce is hovering around 210F, just below 100C, on I-10 doing 85mph or so with fluctuations for traffic (late summer, southeast US ambient temps). This should have the oil right at the 5 cSt, where Mobil advertises, and Toyota engineers expect it to be. If I ever start to see temps high enough to take it out of spec for the grade, then I’ll definitely consider using the 0w-16, temporarily at least.

At this point, my tentative conclusion, subject to change if evidence shows otherwise, is that the A25A engine in this car almost never produces conditions under which a higher vis oils would produce meaningfully better lubrication.

 

[kschachn]

The bottom line is that Toyota engineers understand Tribology and know thicker oils provide more engine protection with more demanding engine use, and they don't even put a viscosity limit on how thick an owner could decide to use based on their OM statement. The reason they say to change it back to 0W-8 at the next oil change is because they used 0W-8 to qualify it for CAFE credits and part of CAFE requirements is they must "recommend" and push the use of that recommended oil viscosity - also the reason it's also printed on the oil filler cap.

This is exactly correct. The only way to argue against this is to deny basic physics along with a complete misunderstanding of EPA requirements for fuel economy measurement.

 

[kschachn]

Respectfully, you’re assuming a bit too much. Are not both cold starts, and the frequent on-off cycling of hybrid engines also “demanding” engine uses? As for the weasel words about going back to 0w-8 after using a thick 16, don’t forget, there can be, and very frequently are, multiple reasons or motivations behind a particular decision. Sure, that approach allows them to tell regulators, “see, we’re encouraging customers to use the lower vis oils.” But at the same time, you we simply cannot rule out the possibility that the characteristics of the 0w-8 oil actually do as good, or even a better job of lubricating this engine during the operations it’s going to see during 95+% of its life.

A point to consider: I keep a ScanGauge-III hooked up to my OBD port at all times. One of the parameters I keep displayed on the Home screen is OIL TEMPERATURE. In normal around town driving, the highest temps I’ll see are around 180F. The highest I’ve thus far been able to produce is hovering around 210F, just below 100C, on I-10 doing 85mph or so with fluctuations for traffic (late summer, southeast US ambient temps). This should have the oil right at the 5 cSt, where Mobil advertises, and Toyota engineers expect it to be. If I ever start to see temps high enough to take it out of spec for the grade, then I’ll definitely consider using the 0w-16, temporarily at least.

At this point, my tentative conclusion, subject to change if evidence shows otherwise, is that the A25A engine in this car almost never produces conditions under which a higher vis oils would produce meaningfully better lubrication.

There is exactly one reason 8-grade oil is listed in the owner’s manual and exactly one reason the manual is worded the way it is.

 

[ekpolk]

This is exactly correct. The only way to argue against this is to deny basic physics along with a complete misunderstanding of EPA requirements for fuel economy measurement.

Is a cold morning start in, say, Northern Michigan in February not a “demanding” lubrication scenario? What exactly does “better protection” mean. Are you suggesting that hot, high load situations are the ONLY “demanding” situations that challenge an engine’s lubrication system? Of which oil is just one part? You have to be precise with your terms, and with the context in which you use them. If you don’t, this just devolves into a “tastes great, less filling” subjective argument and little more.

As for 0w-8 oil used in an A25A engine, which seems NOT to have any tendency to overheat its oil, what relative meaningful benefit can be proven by use of a higher vis oils? Toyota has obviously validated the use of 0w-8 oil in this engine. Equally obvious is that YES, CAFE requirements from the government ARE FOR SURE INVOLVED. It does not follow, however, that an oil that contributes to CAFE compliance, does not also perform well as a lubricant. And nowhere, ever, did I say or suggest that one cannot use a higher vis oils in this or any other engine. I do take issue with the idea that “better protection” and “demanding applications” have only one meaning, and that one meaning just happens to always point to the use of a higher viscosity oil.

 

[kschachn]

Is a cold morning start in, say, Northern Michigan in February not a “demanding” lubrication scenario? What exactly does “better protection” mean. Are you suggesting that hot, high load situations are the ONLY “demanding” situations that challenge an engine’s lubrication system? Of which oil is just one part? You have to be precise with your terms, and with the context in which you use them. If you don’t, this just devolves into a “tastes great, less filling” subjective argument and little more.

As for 0w-8 oil used in an A25A engine, which seems NOT to have any tendency to overheat its oil, what relative meaningful benefit can be proven by use of a higher vis oils? Toyota has obviously validated the use of 0w-8 oil in this engine. Equally obvious is that YES, CAFE requirements from the government ARE FOR SURE INVOLVED. It does not follow, however, that an oil that contributes to CAFE compliance, does not also perform well as a lubricant. And nowhere, ever, did I say or suggest that one cannot use a higher vis oils in this or any other engine. I do take issue with the idea that “better protection” and “demanding applications” have only one meaning, and that one meaning just happens to always point to the use of a higher viscosity oil.

What a mess. This is what you get when people do not really understand the issue but rely on some outside notion to support their assertions.

An oil with a higher HT/HS always produces less wear. It also allows for some headroom for fuel dilution in those vehicles here this is an issue - which includes many newer engines. The one, and only real benefit to lower viscosity oils is less fuel consumption. If that is your singular goal then go for it.

 

[ekpolk]

What a mess. This is what you get when people do not really understand the issue but rely on some outside notion to support their assertions.

An oil with a higher HT/HS always produces less wear. It also allows for some headroom for fuel dilution in those vehicles here this is an issue - which includes many newer engines. The one, and only real benefit to lower viscosity oils is less fuel consumption. If that is your singular goal then go for it.

A mess indeed. I notice that you were not able or willing to define “better protection” or “demanding applications”. The crickets are awfully loud. Generalizations like “a higher HT/HS always produces less wear” are unhelpful. Accepting that as a blanket principle that applies “always”, then we should all just load up our engines SAE 60 oil and call it a day. A higher HT/HS isn’t going to be meaningful in an engine that does not generate conditions in which high temperature and/or high shear conditions are a particular threat. If they are, then that’s another story. In the Camry, the total FWD output is 225hp, of which 185 or so comes from the ICE. Although I’m only 1500 miles into my experience with this engine, I have not been able to get oil temp above about 210F and I doubt I’ve exceeded 5k rpm more than a dozen times. Not exactly conditions that demand a high HT/HS rating. And even if that “always produces less wear” generalization has a grain of correctness, in something like a Camry, it probably amounts to the difference between 5.0 or 5.01 million miles out of the engine — in other words, essentially a wholly theoretical benefit.

 

[ekpolk]

And, I should add, I very much fully understand how the EPA is pushing car makers to shave small percentages from models, multiplying across large numbers, and so forth. Neither the physics, nor the politics, are hard to understand.

 

[OVERKILL]

Accepting that as a blanket principle that applies “always”, then we should all just load up our engines SAE 60 oil and call it a day.

Well no, you still have to use the appropriate Winter grade for the anticipated ambient conditions.

A higher HT/HS isn’t going to be meaningful in an engine that does not generate conditions in which high temperature and/or high shear conditions are a particular threat.

Rod bearings produce high temp, high shear conditions, that's what the test is designed around and why we test for it. "Threat" is relative, design changes to allow the use of thinner and thinner oils while maintaining acceptable levels of wear are made, such as the fitment of wider bearings and the use of special coatings. That said, the only regime of no wear is hydrodynamic, so the more components that are operating in hydrodynamic vs mixed and boundary, the lower the overall wear level is.

If they are, then that’s another story. In the Camry, the total FWD output is 225hp, of which 185 or so comes from the ICE. Although I’m only 1500 miles into my experience with this engine, I have not been able to get oil temp above about 210F and I doubt I’ve exceeded 5k rpm more than a dozen times. Not exactly conditions that demand a high HT/HS rating. And even if that “always produces less wear” generalization has a grain of correctness, in something like a Camry, it probably amounts to the difference between 5.0 or 5.01 million miles out of the engine — in other words, essentially a wholly theoretical benefit.

As noted above, the greater percentage of components that are operating in hydrodynamic, the less the overall amount of wear. The amount of wear goes from (from least to most) hydrodynamic (none) -> mixed -> boundary (most). However, it has been determined that various coatings and or additives/compounds allow for lower friction in mixed than in hydrodynamic (fluid friction being higher than sliding friction in this case), which means a small incremental increase in fuel economy above and beyond just the lower power losses from thinner oil. This compounded byproduct is why there is the continued pursuit of thinner and thinner lubricants, the benefits to fuel economy, which are particularly pronounced during warm-up where the oil is considerably thinner.

Of course super thin oils also introduce other challenges, such as deposit formation, as the ultra low viscosity base oils are very volatile, which is why there were Noack carve-outs for some of the grades. This can lead to an increased propensity for coking in the piston ring lands.

To your point about "but does it matter", that's ultimately why it can be done. People aren't keeping vehicles 500,000 miles generally, so the horizon for longevity isn't pushed out that far.

Maybe a heavier oil and/or more phosphorous would have prevented the lobe wear on @ThirdeYe's Accord, observed at 660,000 miles:

T

Thread 'My 2007 Accord with 666,800 miles (Valvetrain Shots)'

Oct 31, 2024

I attempted to change the valve cover gasket on my long-leaking high-mileage Accord yesterday, but one of the nuts holding the valve cover on was stripped and would not come off. I decided to take it in to the dealer to have them do it, and adjust the valves while it was there. I asked them to take some photos while the cover was off, and here is what they sent me. In the 95k miles I've owned the car, I haven't adjusted the valves or had the valve cover off. I am not sure if the valves were ever adjusted before. The timing chain is original, as far as I know. The previous owner put 571k...

• ThirdeYe
• Replies: 77
• Forum: Mechanical/Maintenance Forum

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• 
• 

But was Honda considering that when they spec'd the lubricant they did for it? Unlikely, because that's not the average anticipated lifespan expected for the vehicle/engine. Heck, they had a whole paper on "acceptable wear" in their pursuit of greater fuel economy through the use of 0W-12 and 0W-8 that Shannow shared on here years back.

It's an acceptable trade-off, lower lifetime fuel consumption, for an increase in lifetime wear that will likely be irrelevant to the majority of owners.

 

[The Critic]

Maybe a heavier oil and/or more phosphorous would have prevented the lobe wear on @ThirdeYe's Accord, observed at 660,000 miles:

T

Thread 'My 2007 Accord with 666,800 miles (Valvetrain Shots)'

Oct 31, 2024

I attempted to change the valve cover gasket on my long-leaking high-mileage Accord yesterday, but one of the nuts holding the valve cover on was stripped and would not come off. I decided to take it in to the dealer to have them do it, and adjust the valves while it was there. I asked them to take some photos while the cover was off, and here is what they sent me. In the 95k miles I've owned the car, I haven't adjusted the valves or had the valve cover off. I am not sure if the valves were ever adjusted before. The timing chain is original, as far as I know. The previous owner put 571k...

• ThirdeYe
• Replies: 77
• Forum: Mechanical/Maintenance Forum

• 
• 
• 

No, that was a known issue with K24 camshaft's from that era. Though, the issue was most prevalent in the early ones.

 

[OVERKILL]

No, that was a known issue with K24 camshaft's from that era. Though, the issue was most prevalent in the early ones.

Right, I know, but my point is: would more AW additives and/or more viscosity have had an impact on the issue and its rate of manifestation, or is the issue wholly delamination of the surface hardening due to fatigue? A roller environment isn't zero wear, it's just much lower wear, and requires much lower levels of AW additives to keep wear under control.

 

[ekpolk]

OVERKILL: Thank you for that well thought out response. I agree with the essence of it. Just a couple thoughts for the discussion. My specific mention of SAE 60 (vs mentioning a multi grade with a w component) was that the other poster had suggested that higher vis was “always” better. My point was that it’s certainly NOT always the case, whether that’s transient conditions (like a cold start) or perhaps steady state conditions, as in an engine that just doesn’t need the higher viscosity to live a long, long life (even if there might be a very tiny benefit in using a higher viscosity oil.

Turning to the quality of the very low viscosity oils, and the bases from which they’re made, that’s a very interesting possible discussion. Of course, we can’t call Mobil or Valvoline, get the duty tribologist, and expect a download of business secrets… If only! That said, there’s some tantalizing information in the PDS for the various products. I’ve viewed the docs for the M1AFE, Valvoline and (IIRC) the Eneos 0w-8s. An interesting comparison is between AFE 0W-8 and 0w-30. For the 0w-8, the 100F cSt is 5, the pour point is below -60 (!) and the flash point is 232 degrees. For the 30, it’s 10.2, -42 and only 225 on the flash point. I’d really like to know what they’re doing to make the 0w-8 behave so well, compared to its 30wt sibling!

 

[kschachn]

OVERKILL: Thank you for that well thought out response. I agree with the essence of it. Just a couple thoughts for the discussion. My specific mention of SAE 60 (vs mentioning a multi grade with a w component) was that the other poster had suggested that higher vis was “always” better. My point was that it’s certainly NOT always the case, whether that’s transient conditions (like a cold start) or perhaps steady state conditions, as in an engine that just doesn’t need the higher viscosity to live a long, long life (even if there might be a very tiny benefit in using a higher viscosity oil.

Turning to the quality of the very low viscosity oils, and the bases from which they’re made, that’s a very interesting possible discussion. Of course, we can’t call Mobil or Valvoline, get the duty tribologist, and expect a download of business secrets… If only! That said, there’s some tantalizing information in the PDS for the various products. I’ve viewed the docs for the M1AFE, Valvoline and (IIRC) the Eneos 0w-8s. An interesting comparison is between AFE 0W-8 and 0w-30. For the 0w-8, the 100F cSt is 5, the pour point is below -60 (!) and the flash point is 232 degrees. For the 30, it’s 10.2, -42 and only 225 on the flash point. I’d really like to know what they’re doing to make the 0w-8 behave so well, compared to its 30wt sibling!

A higher HT/HS always reduces wear. That’s the fact. If it’s not a concern or if the reduction isn’t significant to you that’s a different matter.

And automakers are not making a 0W-8 oil “behave so well” compared to a 30-grade. They incorporate design changes to engines to allow them to tolerate the lower grade without incurring excessive wear. This is distinct from and completely different then how the film thickness prevents wear.

If you’re “tantalized” by the PDS and by flash points I’m not sure what else to say.

 

[The Critic]

A higher HT/HS always reduces wear. That’s the fact. If it’s not a concern or if the reduction isn’t significant to you that’s a different matter.

And automakers are not making a 0W-8 oil “behave so well” compared to a 30-grade. They incorporate design changes to engines to allow them to tolerate the lower grade without incurring excessive wear. This is distinct from and completely different then how the film thickness prevents wear.

All of this is academically true. And OEM's have also improved surface finishes, changed oil pump designs and incorporated bearing coatings (e.g. IROX 2) that have allowed for wear issues to be controlled for the duration of the intended engine lifespan.

So yes, while a higher HT/HS oil may reduce theoretically reduce wear, any additional wear reductions are likely to be irrelevant for the average consumer's ownership duration.

 

[kschachn]

All of this is academically true. And OEM's have also improved surface finishes, changed oil pump designs and incorporated bearing coatings (e.g. IROX 2) that have allowed for wear issues to be controlled for the duration of the intended engine lifespan.

So yes, while a higher HT/HS oil may reduce theoretically reduce wear, any additional wear reductions are likely to be irrelevant for the average consumer's ownership duration.

Oil pump changes are there to reduce horsepower requirements. They don’t directly facilitate the use of lower viscosity oils. Any changes to the pump structure would be to prevent excessive wear of the internals.

But the rest I agree with. Most people keep their vehicles for significantly shorter periods than I do. And even for me it’s likely not an issue for wear as long as fuel dilution isn’t an issue.

 

[ekpolk]

A higher HT/HS always reduces wear. That’s the fact. If it’s not a concern or if the reduction isn’t significant to you that’s a different matter.

And automakers are not making a 0W-8 oil “behave so well” compared to a 30-grade. They incorporate design changes to engines to allow them to tolerate the lower grade without incurring excessive wear. This is distinct from and completely different then how the film thickness prevents wear.

If you’re “tantalized” by the PDS and by flash points I’m not sure what else to say.

Don’t read more into my comments than is there. As I clearly indicated, two lone data points are NOT something from which one can draw firm conclusions. They do, however, differ notably from what appears in the cases of higher viscosity oils, but again, since we’re not going to get any trade secret info from anyone, whether they indicate substantial differences, who knows. If oils and how they behave is not INTERESTING to you, why be a member here???

As the others have indicated, even assuming the broad brush statement about HT/HS is always true in all cases, again, it’s academic. Toyota obviously validated the use of 0w-8 oil for use in this engine. It would be management malpractice if they did not. AND 0w-8 has been in use in Japan (I know, I know, different usage patterns there…) for ten years now. My money is on this being yet another replay of all the Chicken Little hysteria and panic that spewed forth upon the wide spread specification of 5w-20 oils by Honda and Ford back in the late 90s. We’re now more than a QUARTER CENTURY past that change, and we’re STILL NOT seeing a pattern of mass failures from “thin” oil in those engines. Add to that the fact that we have had the same loooooong period of time for engine improvements, and I expect the same, or a better, outcome: lots of daily driver Camrys reaching a ripe old age, running fine and burning no oil if correctly maintained.

 

[kschachn]

Don’t read more into my comments than is there. As I clearly indicated, two lone data points are NOT something from which one can draw firm conclusions. They do, however, differ notably from what appears in the cases of higher viscosity oils, but again, since we’re not going to get any trade secret info from anyone, whether they indicate substantial differences, who knows. If oils and how they behave is not INTERESTING to you, why be a member here???

As the others have indicated, even assuming the broad brush statement about HT/HS is always true in all cases, again, it’s academic. Toyota obviously validated the use of 0w-8 oil for use in this engine. It would be management malpractice if they did not. AND 0w-8 has been in use in Japan (I know, I know, different usage patterns there…) for ten years now. My money is on this being yet another replay of all the Chicken Little hysteria and panic that spewed forth upon the wide spread specification of 5w-20 oils by Honda and Ford back in the late 90s. We’re now more than a QUARTER CENTURY past that change, and we’re STILL NOT seeing a pattern of mass failures from “thin” oil in those engines. Add to that the fact that we have had the same loooooong period of time for engine improvements, and I expect the same, or a better, outcome: lots of daily driver Camrys reaching a ripe old age, running fine and burning no oil if correctly maintained.

I do find it interesting how they behave. It’s just that $30 uncontrolled spectrographic analyses, tables of typical values on a PDS, and ad hoc Internet and YouTube “tests” and testimonials are not my metrics.

 

[BMWTurboDzl]

I'm gonna hijack this slightly.

Someone school me: when an engine is designed from the ground-up, is it designed with a specific viscosity in mind, or does that question get answered more towards the end of the engineering process?

In stupid terms: "We're designing this engine around a 0w-20 oil." Or, "Now that we see what we have in schematics, materials, initial prototype build etc, it's clear that 0w-20 is going to be sweet spot for this engine."

Automakers sell engines worldwide and not all markets have the same FE requirements or oil choices so with a new engine they will design it so it can run on 20 grade but not that it MUST run on a 20 grade. Oil grade is just one piece of the puzzle. Other pieces can be a cylinder deactivation system, VVT with solenoids that are operated electronically rather than using oil pressure, electronic water/oil pumps, oil coolers, EPS.

 

[thastinger]

On my vehicles over the decades, I have found if I stray too far to the "thick side" oftentimes the engine doesn't respond properly or to the original intent - as it had run when factory new.

I am reminded of this very fact as I recently had to do this with our Ford 2.0L when I installed Mobil 1 5W30. I ended up draining a bit and substituting in its place I chose a companion in Mobil 1 0W16. All to save the newish sump rather that start over.

The opposite can also be true, as the 0w20 508 00 VW 1.4L required some help but toward the more viscous direction.

Have not seen shearing of oil pump shafts (lol) but I have noted weeping filter gaskets - along with the aforementioned performance issues.

I (referencing MOTUL) have come to call this viscosity tailoring. An adjustment sometimes required for optimum performance and response when the engine is at operating temperature. Just as off the shelf trousers are not a one size fits all product, So can be that container of motor oil.

This may all seem odd or unnecessary, but I am at certain time or circumstance compelled to act. - Arco

I read all that in a British accent.

 

[ZeeOSix]

Is a cold morning start in, say, Northern Michigan in February not a “demanding” lubrication scenario? What exactly does “better protection” mean. Are you suggesting that hot, high load situations are the ONLY “demanding” situations that challenge an engine’s lubrication system? Of which oil is just one part? You have to be precise with your terms, and with the context in which you use them. If you don’t, this just devolves into a “tastes great, less filling” subjective argument and little more.

Don't confuse the W grade with the KV100 grade. They are two different grade ratings, and two different requirements for the oil. Both the W rating and the KV100/HTHS performance needs to be adequate for proper lubrication and engine protection. Obviously the lower the W grade, the better it does in cold start-ups, and the higher the KV100/HTHS grade the better it produces the required MOFT between moving parts to keep them separated for better wear protection. On the flip side, the more MOFT there is, the more power is lost to shear the oil which can result in less fuel economy. That's why the auto makers are going as low as possible to get as much fuel economy as possible and still try to give "adequate" lubrication and engine wear protection. But they are basically operating on the edge when doing so.

As for 0w-8 oil used in an A25A engine, which seems NOT to have any tendency to overheat its oil, what relative meaningful benefit can be proven by use of a higher vis oils? Toyota has obviously validated the use of 0w-8 oil in this engine. Equally obvious is that YES, CAFE requirements from the government ARE FOR SURE INVOLVED. It does not follow, however, that an oil that contributes to CAFE compliance, does not also perform well as a lubricant. And nowhere, ever, did I say or suggest that one cannot use a higher vis oils in this or any other engine.

Of course the A25A was verified by Toyota to use 0W-8, and it's been specifically designed to use that thin of oil ... many discussions about that here over the years. 0W-8 and 0W-16 have their own ILSAC- 6B designation and logo on the bottle for a reason, because those oils are not meant to be used in other engines not specifically designed for that thin of oil. If the oil never gets over 100C then that obviously is part of the equation to help keep that thin oil in check. Been said many times in these discussions that just cruising around in a benign way isn't very demanding, and will most likely not cause any issues if the oil temps are reasonable. Could still be causing more wear over the life of the engine compared to using a thicker oil (ie, a grade higher).

I do take issue with the idea that “better protection” and “demanding applications” have only one meaning, and that one meaning just happens to always point to the use of a higher viscosity oil.

Fact is, and always will be that higher viscosity equates to higher MOFT, which means moving parts are better separated from each other. That's like one of the most basic physical aspects of Tribology. If 0W-16 instead of 0W-8 was used, it would give more engine protection regardless of the use conditions. Having a bit more MOFT to keep moving parts more separated is added protection. And as mentioned, if there is any fuel dilution then the higher viscosity adds a buffer to help keep the oil viscoity from decreasing too much over the OCI.

 

[ZeeOSix]

My money is on this being yet another replay of all the Chicken Little hysteria and panic that spewed forth upon the wide spread specification of 5w-20 oils by Honda and Ford back in the late 90s. We’re now more than a QUARTER CENTURY past that change, and we’re STILL NOT seeing a pattern of mass failures from “thin” oil in those engines.

Why do you think Ford started specifying 5W-30 starting in the 2021 Coyote V8 when it was specified to use 5W-20 for years? 5W-30 was always speced for the Coyote in Australia. They certainly didn't go up a grade in the USA with CAFE in mind. And there are a lot of Coyote engines used by Ford ... enough to make a big impact on their CAFE credits. There is only one reason to increase the oil viscosity, and that's to give the engine more wear protection.