Can 0w20 handle high RPMs

[y_p_w]

Originally Posted by dareo
For whatever its worth the only time i've seen an engine fail on a 20 weight was a Toyota 4AGE 20 valve being rallied. It already had a ton of abusive miles on it and the owner liked 5w20 for winter street use, ended up taking it to a rally cross in the spring and it threw a rod. Was it the engine's time to go? Or was it the oil? This thing would rev to nearly 8,000 and was never spec'd a 20 weight.

Racing is always kind of an odd thing. I thought that supercompetetive race teams will often use thin oils for qualifying laps, but perhaps shift to a thicker oil for longer race days where the oil might be cooked after an hour of beating it up. Also - that might be the right situation for more frequent oil changes.

And of course the use of more advanced antiwear additives was mentioned. That's probably the one thing that makes thinner oils most acceptable. And why wear from cold starts isn't as bad as it used to be.

 

[ka9mnx]

Originally Posted by PimTac
"What has been said is that a higher rate of decline is considered in making engine oil recommendations using thinner oils. The manufacturer accept the risk based upon their customers usage."





How much of a decline is my question and it may not be answerable. If a engine is expected to last 300,000 miles on 5w30 but only lasts 280,000 on 0w20 then do we blame the oil at that point? There are too many factors involved to only point fingers at the oil.

You are absolutely correct. Junk yards are not becoming overwhelmed with engines running w20 oils and manufacturers and owners are getting full life out of there engines. But. In a perfect world, running in a dyno room, would put to rest the "actual" life of an engine running either oils. Which IS important for folks like me who keep their vehicles forever and don't like re-ringing or replacing bearings in that lifetime.

 

[ekpolk]

Originally Posted by dareo
. . . This thing would rev to nearly 8,000 and was never spec'd a 20 weight.


IMO, that's a pretty major clue there. . . My opinion: This one wasn't the oil or the engine. It was on the owner for failing to use the oil appropriate for his engine under the circumstances in which he operated it.

 

[y_p_w]

Originally Posted by ekpolk
Originally Posted by Bryanccfshr
Where did you come to that extreme conclusion? No one is saying that. What has been said is that a higher rate of decline is considered in making engine oil recommendations using thinner oils. The manufacturer accept the risk based upon their customers usage.


Originally Posted by ekpolk
. . . I'm "for" using the correct oil in the correct application. If I'm against anything, it's nursing unfounded dark fears that a modern engine will certainly die an early death if we don't ignore the manual, substitute our judgment for that of the designers, and use the "thick stuff."



I assume this is what you're reading as "extreme." I may have stated the point with some hyperbole for emphasis, but is this not what's going on? Car makers recommend 20wt, or even 16wt oil for a whole range of models, and have for twenty years. And while it is clear that there are some specific applications where that has proven inadequate, for the most part, it has proven safe and effective, and millions of cars run on 20wt to the end of their useful life, without failing because of using "thin" oil. Yet the doubts persist, and yes, one poster here even suggested I should ignore my OM and use 30wt to get "better protection." BTW, he didn't define "better"...

There may or may not be an actual "higher rate of decline" in one particular engine or another (I doubt any mfr will share that info), or it may be theoretical. How can we even know? Personally, IMO I'm not convinced that the small increased wear is happening in every design. But if it is, it's so miniscule that it has no bearing (sorry...) on the ultimate outcome, then how is it a real concern?

I think it goes both ways. It's not as if using some thicker weight oil ends up destroying engines either. They're actually pretty tolerant of different oil weights, especially given that they have to deal with extremely thick oil at startup. I recall back when Mobil 1 0w30 first came out, Porsche had an agreement to use Mobil 1 and said that any non-specialty weight of Mobil 1 was acceptable given the conditions. That included 0W-30, 5w30, 10w30, and 15W-50. But there may not necessarily be any advantage to the heavier oils, which obviously result in reduced fuel economy. If I've got my Honda grocery getter running 0W-20, what would be the advantage of running 5w30?

Heck - I've seen some pretty out there recommendations for motor oils. The first new car I drove was a 1989 Integra RS, which my parents bought for me to drive in college. I was there as the sales creature went over the owner's manual. Even took out a highlighter to show that it said 5w30, 10w30, and 10W-40. And it wasn't specified in the manual, but I was told that their service department specifically said that they considered 20W-50 to be acceptable and that's what they used when a car was brought in for servicing or just oil changes.

 

[ka9mnx]

Originally Posted by ekpolk
Originally Posted by ka9mnx
Yep. I really don't care about oil grade but pay close attention to HTHS. w20 HTHS, although proven to be adequate, is bordering on not adequate.


Fair enough, the HTHS numbers of the 20wt oils are almost all, predictably, below those of 30wt oils (2.6-2.7ish vs mid-3s for the 30s seems to be typical), but how do we define adequate or not? Is this not one of the key questions?

Years ago when w20 first came out there was a paper that tested engine durability against HTHS. Below 2.5 was dangerous and above 3.5 was wasteful. They stated 3.2 was ideal. Another paper I read years ago by engine builders stated that ALL engines, of the time, were designed around w30. w30 HTHS is 2.9 to 3.5.

I cannot answer your question about "adequate" as I only see it referenced in owners manuals.

 

[y_p_w]

Originally Posted by ekpolk
Originally Posted by dareo
. . . This thing would rev to nearly 8,000 and was never spec'd a 20 weight.


IMO, that's a pretty major clue there. . . My opinion: This one wasn't the oil or the engine. It was on the owner for failing to use the oil appropriate for his engine under the circumstances in which he operated it.

Well - Honda has shifted from their 8000 RPM redline engines to turbos with lower redlines. And feeding 0W-20 into a turbo creates its own issues, which is why they're water cooled. If you look at the Honda engine oil application guide (of which different versions have been posted here) they actually don't backdate their recommendation for 5W-20 to the 1999/2000 Civic Si with the 1.6L DOHC VTEC generating 160 HP. That had an 8000 RPM redline like the Prelude Si and Integra GS-R of about the same era. The S2000 had a 9000 RPM redline and they never spec'ed anything other than 10w30, although I suppose that could include anything including the cheapest "mineral" 10w30 at the time. I don't quite understand why those where 5W-20 is backdated as acceptable, that 0W-20 isn't acceptable other than perhaps they didn't have enough room in the chart.

That being said, I use Mobil 1 0W-40 in my 2004 WRX. But "conventional" 5W-20 in my wife's 2002 Civic. They've had their issues, but none of them engine related, even with a little bit of neglected oil changes.

Still - I get where you're coming at. A 5W-20 or 0W-20 is fine for applications where they're recommended by the manufacturer. Everything is really just a compromise. Maybe it's possible for a minor increase in engine life at the cost of fuel economy and performance.

 

[dave1251]

The point which should be empathized IMO is if the oil tempature is not elevated to the point it does not become too thin it does not matter whether it's a 20 or 70 grade. Thus the subject question is not complete.

 

[ZeeOSix]

Originally Posted by ekpolk
Originally Posted by ZeeOSix
. . . you would see that if holding all things constant, that increasing the viscosity adds protection due to larger MOFT and typically a higher HTHS.

So yes, there is a difference between the level of protection from using oil as thin as possible for reasons driven by CAFE giving "adequate" protection for benignly driven vehicles vs the level given by using a thicker oil. Put 5w30 in those same vehicles and you get some added protection from the increased viscosity factor, regardless if it's "needed" or not. Why do you think the same vehicles sold in other non-CAFE countries show in the oil recommendation specs going all the way up to 40 or 50 wt is acceptable?


1. Again, if any of these "20-recommended" applications actually require that protection, but didn't have it when they needed it -- we would, by now, have seen the evidence -- a pattern of damage and/or failure -- and we have not...

2. Respectfully "back at you": why do YOU think Toyota is now actually specifying 0w-16 oil in the current Camry (and another model I don't recall right now...)??? Why didn't you mention that too? Gee, before long, 20 and 30wt are going to be the "thick stuff" everyone is nostalgically clinging to.

Your (and others have used) the strawman argument that you don't see thousands of dead cars on the road or in junk yards due to using xW-20 oil, and that guys get 250K+ miles on their vehicles using xW-20 oil. Fact is, did anyone actually determine if there was no wear difference in those engines compared to using a thicker oil in them over their lifetime? Like I've said many times, most engines will still run pretty good even if they are technically worn out per the service manual specs. I get the mindset that if the car still runs "good" when it's rusted out or goes to the junk yard then what's the difference. Guess I and some others don't share that mindset. I like efficient oil filters, and I like more than "adequate" MOFT and HTHS oil properties in my engines. I hardly ever settle for things that are borderline "adequate".

I agree with what was said a while back: "... you are displaying an absolute and fundamental misunderstanding of hydrodynamic lubrication."

My comments are all related to the understanding of hydrodynamic lubrication, yet you agree with others that try to show you why oil viscoity matters in hydrodynamic lubrication but you just get belligerent with my comments.

If you've been reading all the T vs T threads, you'd know that Honda also did mechanical engine design changes with the journal bearings to try and maintain adequate MOFT in order to use 0W-16 weight oil

Originally Posted by ekpolk
More seriously, though, your last comment provides an important clue, IMO, about the answer to this whole mess of an "issue": could it possibly be (touch of sarcasm admitted...) that the range of oils that are "acceptable" for most engines is actually quite a bit broader than most might think? I'm reminded of a comment I read long ago, on actual paper somewhere, long before the internet, to the effect that we should use the recommended grade, but it was safe to go "one up or one down." Apart from the few, specific critical applications that obviously do exist, maybe that's been true all along...


Of course a range of oil viscosity is acceptable to use in basically all engines. If it wasn't, you wouldn't see charts that show a whole range of acceptable viscosity (except in the USA because of CAFE agreements). And also, manuals that show a range of viscosity will usually also make the comment that the thicker oils will protect better for more demanding driving conditions. Do the math.

 

[PimTac]

Originally Posted by y_p_w
Originally Posted by ekpolk
Originally Posted by Bryanccfshr
Where did you come to that extreme conclusion? No one is saying that. What has been said is that a higher rate of decline is considered in making engine oil recommendations using thinner oils. The manufacturer accept the risk based upon their customers usage.


Originally Posted by ekpolk
. . . I'm "for" using the correct oil in the correct application. If I'm against anything, it's nursing unfounded dark fears that a modern engine will certainly die an early death if we don't ignore the manual, substitute our judgment for that of the designers, and use the "thick stuff."



I assume this is what you're reading as "extreme." I may have stated the point with some hyperbole for emphasis, but is this not what's going on? Car makers recommend 20wt, or even 16wt oil for a whole range of models, and have for twenty years. And while it is clear that there are some specific applications where that has proven inadequate, for the most part, it has proven safe and effective, and millions of cars run on 20wt to the end of their useful life, without failing because of using "thin" oil. Yet the doubts persist, and yes, one poster here even suggested I should ignore my OM and use 30wt to get "better protection." BTW, he didn't define "better"...

There may or may not be an actual "higher rate of decline" in one particular engine or another (I doubt any mfr will share that info), or it may be theoretical. How can we even know? Personally, IMO I'm not convinced that the small increased wear is happening in every design. But if it is, it's so miniscule that it has no bearing (sorry...) on the ultimate outcome, then how is it a real concern?

I think it goes both ways. It's not as if using some thicker weight oil ends up destroying engines either. They're actually pretty tolerant of different oil weights, especially given that they have to deal with extremely thick oil at startup. I recall back when Mobil 1 0w30 first came out, Porsche had an agreement to use Mobil 1 and said that any non-specialty weight of Mobil 1 was acceptable given the conditions. That included 0W-30, 5w30, 10w30, and 15W-50. But there may not necessarily be any advantage to the heavier oils, which obviously result in reduced fuel economy. If I've got my Honda grocery getter running 0W-20, what would be the advantage of running 5w30?

Heck - I've seen some pretty out there recommendations for motor oils. The first new car I drove was a 1989 Integra RS, which my parents bought for me to drive in college. I was there as the sales creature went over the owner's manual. Even took out a highlighter to show that it said 5w30, 10w30, and 10W-40. And it wasn't specified in the manual, but I was told that their service department specifically said that they considered 20W-50 to be acceptable and that's what they used when a car was brought in for servicing or just oil changes.





Just to add a observation ; our Mazda CX-5 with the 2.5 SkyActiv stays within a fairly small rpm range in most driving situations. Even somewhat brisk acceleration will only get the engine up to 3000 or maybe 3500 rpm. It cruises below 2000 rpm for the most part.

The programming of the transmission and the ECU keeps modern engines in a range that is conducive to fuel efficiency. Even at freeway speeds these engines are hardly working. The only times I see higher rpm is if I'm going up a hill and I'm in sport mode or I am manually controlling the shifts.

 

[ZeeOSix]

Originally Posted by ekpolk
I'm "for" using the correct oil in the correct application. If I'm against anything, it's nursing unfounded dark fears that a modern engine will certainly die an early death if we don't ignore the manual, substitute our judgment for that of the designers, and use the "thick stuff."


Nobody is claiming that dramatic comment ... but they are claiming (backed up by many technical studies and the understanding of tribology) that thicker oils do add wear protection to engines. The xW-20 "recommendation" from the US car manufactures is driven by CAFE (it's been shown with documentation - LINK). It's true that as the thinner oil craze became "standard" practice over the years that some newer engines (like Honda with their 0W-16 drive) have changed design somewhat in order to try and increase reliability in those engines. If oil goes even down a step farther to xW-8 there may be even more engine design changes, along with major anti-wear additive re-formulation to keep engines from damage (ie, not depending on viscosity as much as anti-wear additives).

 

[y_p_w]

Originally Posted by ZeeOSix
Originally Posted by ekpolk
I'm "for" using the correct oil in the correct application. If I'm against anything, it's nursing unfounded dark fears that a modern engine will certainly die an early death if we don't ignore the manual, substitute our judgment for that of the designers, and use the "thick stuff."


Nobody is claiming that dramatic comment ... but they are claiming that (backed up by many technical studies and the understanding of tribology) that thicker oils do add wear protection to engines. The xW-20 "recommendation" from the US car manufactures is driven by CAFE (it's been shown with documentation - LINK). It's true that as the thinner oil craze became "standard" practice over the years that some newer engines (like Honda with their 0W-16 drive) have changed design somewhat in order to try and increase reliability in those engines. If oil goes even down a step farther to xW-8 there may be even more engine design changes, along with major anti-wear additive re-formulation to keep engines from damage (ie, not depending on viscosity as much as anti-wear additives).

But then again we're seeing excellent long term reliability. Does it really matter how we got there? This seems to be more an oil geek discussion than a practical one. Kind of like a friend who was desperate to get the highest speed rated tire for his Ford Probe because he was impressed by numbers.

Engines are pretty much appliances now. Do regular maintenance according the schedule or OLM and you're likely never going to see an oil-related failure even with modern XW-20 motor oils. The exceptions are of course the big screwups like Honda's VCM system.

 

[ZeeOSix]

Originally Posted by y_p_w
Originally Posted by ZeeOSix
Originally Posted by ekpolk
I'm "for" using the correct oil in the correct application. If I'm against anything, it's nursing unfounded dark fears that a modern engine will certainly die an early death if we don't ignore the manual, substitute our judgment for that of the designers, and use the "thick stuff."

Nobody is claiming that dramatic comment ... but they are claiming that (backed up by many technical studies and the understanding of tribology) that thicker oils do add wear protection to engines. The xW-20 "recommendation" from the US car manufactures is driven by CAFE (it's been shown with documentation - LINK). It's true that as the thinner oil craze became "standard" practice over the years that some newer engines (like Honda with their 0W-16 drive) have changed design somewhat in order to try and increase reliability in those engines. If oil goes even down a step farther to xW-8 there may be even more engine design changes, along with major anti-wear additive re-formulation to keep engines from damage (ie, not depending on viscosity as much as anti-wear additives).

But then again we're seeing excellent long term reliability. Does it really matter how we got there?


To some it doesn't matter, to others it does. I could really care less if someone used olive oil in there engine.

My viewpoint is I want some added protection headroom by maintaining a bit more MOFT in my engines - every technical study shows there are decreased wear benefits from higher viscosity. Keeping the wear down just means the engine is in a better state of health ... and I keep my vehicles for 15~20 years so I care how they wear and age. Therefore, I have no problem using 5w30 in engines specified for 5W-20.

 

[ekpolk]

Originally Posted by ZeeOSix
. . .
My comments are all related to the understanding of hydrodynamic lubrication, yet you agree with others that try to show you why oil viscoity matters in hydrodynamic lubrication but you just get belligerent with my comments.
Respectfully, please don't interpret the tone of my comments as belligerent. There is no such intent behind them; and I'm sorry if they come off that way. I'm here like everyone else, with my own background and experience, trying perhaps to learn some stuff, while having fun doing it. Both sides (all sides) of this sort of communication need to realize that, of course, none of our natural non-verbal communication comes through on-screen. Emojis are a very poor substitute.

Originally Posted by ZeeOSix
If you've been reading all the T vs T threads, you'd know that Honda also did mechanical engine design changes with the journal bearings to try and maintain adequate MOFT in order to use 0W-16 weight oil.
Right! I've been aware that car makers, probably all of them in truth, have been making adjustments to the engines so they are properly lubricated with lighter oils. Shouldn't this factor actually reduce the concern some have about using "lighter" oils?

Originally Posted by ZeeOSix
Originally Posted by ekpolk
More seriously, though, your last comment provides an important clue, IMO, about the answer to this whole mess of an "issue": could it possibly be (touch of sarcasm admitted...) that the range of oils that are "acceptable" for most engines is actually quite a bit broader than most might think? ...


Of course a range of oil viscosity is acceptable to use in basically all engines. If it wasn't, you wouldn't see charts that show a whole range of acceptable viscosity. And also, manuals that show a range of viscosity will usually also make the comment that the thicker oils will protect better for more demanding driving conditions. Do the math. :
(I added the bold italics). We're ALMOST agreeing!

I notice two things about how this goes. First, the language that actually appears in the manual doesn't say that (though it MIGHT be fairly inferred). It's much slipperier than that. In the 2018 Prius manual, it doesn't say it "will protect better", instead, it suggests that "higher viscosity" may be "better suited" for "high speed" or "extreme load conditions". This mealy-mouthed garbage does not rule out "better protection" assuming that's reasonably defined. BUT, it also raises more questions than it answers. It does not offer (not in the US manual) a higher vis alternative. It says "may" not "will". Then it says, "better suited" which offers zero suggestion of how or when I higher vis oil might offer a worthwhile benefit -- or just a clear "better protection". And just what are "high speeds" or "extreme load conditions" for this car. The manual for the 18 does not allow towing trailers, so just what DO they consider an extreme load?

My usage, including what my eyes and ears tell me, suggest that I need to see a lot more before I conclude that I should rewrite "may be better suited" into "I'd better or else..."

Thanks for your input Z06, the more the merrier. Now, if you want to see some belligerence, let's find that old "20wt = bad honing oil" guy from around 2000 or so...

 

[ekpolk]

Originally Posted by ZeeOSix
Originally Posted by ekpolk
I'm "for" using the correct oil in the correct application. If I'm against anything, it's nursing unfounded dark fears that a modern engine will certainly die an early death if we don't ignore the manual, substitute our judgment for that of the designers, and use the "thick stuff."


Nobody is claiming that dramatic comment .... ...


It's way, way better on this board than many others, but there are plenty of people who've made, or still make, this argument in one form or another, despite my hyperbolic phrasing. The "honing oil guy" (hey, I can call him HOG!) was the first I recall seeing, at the dawn of my "life on the internet," and probably the most extreme. I first met HOG not log after curiously entering "motor oil" as one of my first searches from within the confines (crib rails) of AOL! It's been a while. Anyway, I hear echos of that point, essentially summarized as "if it's a 20 [or less] it's automatically deadly poison for your engine" even today.

 

[y_p_w]

Originally Posted by ekpolk
Right! I've been aware that car makers, probably all of them in truth, have been making adjustments to the engines so they are properly lubricated with lighter oils. Shouldn't this factor actually reduce the concern some have about using "lighter" oils?

Ford actually backdated their 5W-20 recommendations to many early 90s engines.

I also recall that the original Mobil 1 was 5W-20. They recommended it for almost all application.

 

[ka9mnx]

Originally Posted by y_p_w
Originally Posted by ekpolk
Right! I've been aware that car makers, probably all of them in truth, have been making adjustments to the engines so they are properly lubricated with lighter oils. Shouldn't this factor actually reduce the concern some have about using "lighter" oils?

Ford actually backdated their 5W-20 recommendations to many early 90s engines.

I also recall that the original Mobil 1 was 5W-20. They recommended it for almost all application.

Yep. Back spec'd my 93 F150 and I tried it. Didn't work out very well. I used the original Mobil 1 5w-20 in '76. Said it "outperformed 10w-40" right on the can (I still have one). Shannow noted to me that 5w-20 back then was like 10w30 now. Worked real well in my I6 '58 Ford.

 

[ekpolk]

Originally Posted by ZeeOSix

Your (and others have used) the strawman argument that you don't see thousands of dead cars on the road or in junk yards due to using xW-20 oil, and that guys get 250K+ miles on their vehicles using xW-20 oil. Fact is, did anyone actually determine if there was no wear difference in those engines compared to using a thicker oil in them over their lifetime? Like I've said many times, most engines will still run pretty good even if they are technically worn out per the service manual specs. I get the mindset that if the car still runs "good" when it's rusted out or goes to the junk yard then what's the difference. Guess I and some others don't share that mindset. I like efficient oil filters, and I like more than "adequate" MOFT and HTHS oil properties in my engines. I hardly ever settle for things that are borderline "adequate".

I agree with what was said a while back: "... you are displaying an absolute and fundamental misunderstanding of hydrodynamic lubrication."

My comments are all related to the understanding of hydrodynamic lubrication, yet you agree with others that try to show you why oil viscoity matters in hydrodynamic lubrication but you just get belligerent with my comments.


I forgot to address this. This would only be a strawman argument if it could be established that virtually all the cars that go to the yard, and having been fed 20wt oil, are in a more advanced state of wear than they would be be had they been fed 30wt oil or greater. That, I strongly suspect, can't be proven either way. I suspect, IMO, that there are cars of both descriptions, with or without "advanced" wear, but at the end of the day, that's essentially unknowable.

Continuing our foray into the terminology of argumentation,

your position is actually a "red herring". You're focusing on the unknowable state of the cars in the junkyard, while not addressing the fact that we've simply not seen the pattern of early engine failures (pre junkyard) that ought to exist by now, if 20wt wasn't performing well generally. THAT'S what's not there, and what's so telling at this point. In short, the existence and/or extent of "advanced wear" is unknowable, whereas the lack of wide-spread thin-oil-induced early car death knowable, and in fact, known.

And one point of clarification: are you saying that while remaining safely in hydrodynamic lubrication, 20s are providing lesser protection than the 30s, that the 20s are allowing the bearings to experience boundary lubrication more often than would a 30, or perhaps a mix of both. Or something else altogether? Shannow, if you get this far -- feel free to jump in please!

Too much time on my hands today...

 

[ekpolk]

Originally Posted by y_p_w

Ford actually backdated their 5W-20 recommendations to many early 90s engines.

I also recall that the original Mobil 1 was 5W-20. They recommended it for almost all application.


Toyota did the same too. There's a detailed chart summarizing in detail the result of their back-spec-ery, but I can't find it at the moment. Looks sorta like the Honda chart above but with dots instead of bars.

I eyeballed that original M1, in the shiny metal cans, not noticing at the time what it's vis actually was. By the time I first used it, it was 5w30 in round plastic bottles.

 

[Shannow]

FFS...the "pile of failed engines"..."junkyard full of"...is ridiculous hyperbole slippery slope strawman that this board thrives on and certainly doesn't prove ANY point whatsoever.


It's utterly pointless trying to discuss anything in these threads.

Point to CAFE documentation...."show me the pile of failed engines"
Point to the EPA information..."show me the pile of failed engines"
Point to the NHTSA paper..."show me the pile of failed engines"
Point to Honda Papers..."show me the pile of failed engines".


So the only way to prove a fundamental engineering principal (that somehow is equivalent to evolution theory) is to personally dismantle a range of engines that have been run on various grades ????

Please...that's ludicrous.

I'll spin it....please pull apart a pile of failed engines and demonstrate that 20s, 16s, and 12s provide EXACTLY THE SAME WEAR PROTECTION...in spite of what the parties that I listed offer in their statements and papers...please prove it...it's your view.

 

[ZeeOSix]

Originally Posted by ekpolk
... the language that actually appears in the manual doesn't say that (though it MIGHT be fairly inferred). It's much slipperier than that. In the 2018 Prius manual, it doesn't say it "will protect better", instead, it suggests that "higher viscosity" may be "better suited" for "high speed" or "extreme load conditions". This mealy-mouthed garbage does not rule out "better protection" assuming that's reasonably defined. BUT, it also raises more questions than it answers. It does not offer (not in the US manual) a higher vis alternative. It says "may" not "will". Then it says, "better suited" which offers zero suggestion of how or when I higher vis oil might offer a worthwhile benefit -- or just a clear "better protection". And just what are "high speeds" or "extreme load conditions" for this car.


They wouldn't put any statements in the owner's manual (regardless of how it's worded) if thicker oil didn't add engine protection. They just can't tell you or recommend it all the time (knowing it gives better protection regardless of vehicle use conditions) because of agreements with the EPA/CAFE (letter linked in a previous post).