I dont know about studies, but when I see my 0w-20 having a drop in viscosity by more than 2 cSt and 4-5% fuel, the 5w-30 is just to offset the viscosity loss.
is there any benefit of going 'thicker' if uoa already checks out?
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The oil specs out by design as a 0w based on the base stocks used to meet spec and such I'd think. It's also a one size fits all for the application since selling a 10w20 would not only confuse the heck out of the general public(stupid people stay stupid) and no sense having a 5w20 if you can get it to a 0 for the frozen north.
Blaming everything on CAFE is as asinine and antiquated as those viscosity vs. temp charts in owner's manuals. Common sense dictates you use the oil the manufacturer requires as they know more than you.
edyvw
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I mean, fine, sure, but logistics, cost etc. 10W20 in Miami or 0W20 is irrelevant, but issues are elsewhere for blenders, companies.
To answer your question, even with 10k OCI's the oil is during it's job IMO. I wouldn't change anything personally.
https://bobistheoilguy.com/forums/threads/2021-vw-tiguan-2-0-8037miles-vw-oem-508-00-0w20.371353/
Not really as it’s exactly the reason for lower viscosity oils. There is no technical or mechanical benefit besides fuel economy, lower HT/HS isn’t better in any way other than that. Manufacturers don’t “require” a grade they recommend them, and the recommendations are not always being made for technical reasons. Just read one of the several CAFE award letters posted here and you’ll see exactly why the owner’s manuals are written the way they are.
People keep trying to ascribe it to some technical requirement (including calling any other comments as “asinine”) but that doesn’t make it any more true. The one and only benefit to a thinner oil is fuel economy and that’s it.
Actual common sense is often missing from this discussion and when it comes down to it, that’s exactly the intent of CAFE wording.
Fuel economy is a reason. Thinking about it, the engines deliver better fuel economy because they run with less resistance... they run better. If CAFE were the whole story, and the manufacturers were simply running in lockstep under the authoritarian rule of the regulators, they would "require," not recommend.
There are lots of engines out there and there is variety in oil specs to find what is best, but the fact is that for all the talk of film strength, there is no example to be found of a thinner oil causing engine failure. While engines may have had their recommendations change from thicker to thinner oils over the years for the sake of fuel economy, it does not mean that engines have not been designed to work perfectly with the the newer oils.
Can we agree that most folks will do fine following their manufacturer's recommendation(s)... in the country in which the car was purchased.
On the poster's original question, I would rephrase it as "Should I use a thicker oil than the manufacturer recommends, for no reason whatsoever?" That answer is no.
It’s film thickness, not film strength. And anyone can use a higher HT/HS if they wish to reduce wear. That’s a good enough reason for me, especially with engines that are prone to fuel dilution.
We could argue about CAFE being the reason for thinner oils, there will be no end of this debate. Instead, specific examples like Honda DI engine that dilutes oil with gas and drops viscosity. So even if you want to use 0w-20 per manufacture, you can put 5w-30 and it will have viscosity of 0w-20. The answer is not that simple and requires looking at specific engines.
Is there ANY evidence it's needed though? Where is the data to point at X engine running Y viscosity oil in the real world produced Z result? As far as I can tell, Xw20 is just fine and produces no worse result then running a higher grade. A HT/HS number is not a magic indication your engine will last longer on wear be it bearing or otherwise alone.
As far as you can tell? You mean looking at uncontrolled $30 spectrographic analyses? That’s not how you measure wear as related to HT/HS.
Laboratory results using a proper standardized test show a direct correlation between wear and HT/HS. And yes when we are discussing grade it is a “magic indicator”. That is what we’re talking about, right?
No one reduces wear with a decreased MOFT.
Do we know that "thicker" oils are less impacted by fuel dilution? On this topic, not really part of this thread, the most ready solution to fuel dilution is increasing frequency of oil changes.
I think its both, higher viscosity and more frequent oil changes. The viscosity drops pretty quickly, the oil change would be too frequent
Well, probably somewhere between 0W8 and 20W60
Seriously, that is a more profound question that it might seem. The fact is that there is a range of viscosities, and both thicker and thinner choices that what is being contemplated. Most folks would go along with the idea that there are oil choices that are too thick, or too thin. I personally think that 0W20 oils are excellent, when specified for the car. If you twisted my arm, I would admit that fuel economy is not very much greater, and that most folks can go to 0W30 or 0W50 and it will not make a measurable difference.There are secondary detrimental effects of fuel dilution such as VII degradation, but for the most part it is simply the dilution of a higher viscosity fluid by one with a lower viscosity.
The most ready solution to me is to use a viscosity that will resist going out of grade. I'd rather do that than spend money on extra oil changes.
Thicker could be better for a high heat situation (think racing or towing) where the heat of combustion raises the oil temp. If you look at the viscosity of a "thicker" oil at 300 F, you may find that the oil is similar to the viscosity of the "thinner" oil when the oil temp is at a more normal 200 F. IOW: a certain viscosity may indeed be "ideal", and you choose the viscosity that provides that ideal depending upon the oil temps your engine is going to be experiencing.
The distance in kinematic viscosity between motor oil and gasoline is vast. The distance between
W20 and W30 is very small comparatively, and admittedly variable. What this means is that the second order effects you mentioned and the nature of the resultant fluid as miscible fuel enters gasoline, its very small mathematically.
Personal choice is great, but I would point out that "extra" oil changes definitively solve the fuel dilution problem immediately. Higher viscosity oil maybe helps, maybe resists going out of grade. All of that presupposes that the engine will experience wear and damage due to engine oil weight... which is just short of being a fallacy.
You would have to chAnge oil like ever 1000 miles, its not sustainable.
What? It would be a fallacy only for those who deny the physics of film thickness. Every published paper shows there is a direct correlation between HT/HS and wear. Please provide a link to any study that shows the contrary.
You most certainly can damage an engine by using an oil with insufficient MOFT. The oil film is what prevents metal-to-metal contact.
You make some bizarre statements including others that I didn’t quote.
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