Why does xw20 and xw30 show essentially the same/similar UOA but people blame cafe?

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hello i did some reading and it seems like due to fuel economy reasons and cafe, manufacturers prescribe lighter oil requirements to slightly increase MPG. However tons of people say/think that 0w20 does not provide the same amount of protection as a 0w30 for example. my noob question is however wouldnt the uoa of a 0w20 be WORSE then a 0w30 if 0w20 was too light/thin and not protecting enough? because less protection ofc would mean more engine wear and that would ofc show in a UOA

or am i wrong about something?

thx
 
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Since Xw20 oils have been widely adopted over the last 10 years, maybe a better approach to address the 'Xw20 doesn't protect enough' crowd would be to look at the average age of vehicles on the road.
if the Xw20 is truly inferior, overall vehicle age would decrease because the Xw20 is not good enough to provide long life and the vehicles would be off the road.

And yet the average age of a used vehicle is the oldest it has ever been. So that Xw20 must be doing something right. No matter what the naysayers are spouting.
 
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I used to be in the thick camp but I'm not anymore. The difference between API w30 and w20 is very little, just look at the operating CST 100 ranges. Sure, theres a difference in HTHS. But for the average driver with an automatic dropping revs as fast as possible, this makes no difference. Use what they spec, unless you're hitting the track or something.
 
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Agreed.
I just wish people would come with some kind of data to support their position and not just their feelings and opinions.
The facts have already been presented and discussed numerous times, the only way to spark up yet another thick vs. thin discussion is to ignore the facts and resort to feelings.

On the other hand the OP mostly asked about UOA results and the answer is that a UOA isn’t the correct tool for the job.
 
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Because XX-20 engine oils protect engines absolutely fine and across an automaker's fleet, -20 oils provide higher fuel economy when extrapolated across ALL of their models.
 
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Agreed.
I just wish people would come with some kind of data to support their position and not just their feelings and opinions.
Lots of facts and data here, if a person is willing to do their homework and search for it.
 
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Agreed.
I just wish people would come with some kind of data to support their position and not just their feelings and opinions.
There have been plenty of studies and info posted on this chat board showing that thinner oil can result in more wear due to less MOFT between moving parts. Oil viscosity is a direct factor in the resulting MOFT between moving parts, and that's the only thing that keeps parts from contacting each other. Just go do a Google search of "engine wear vs oil viscosity" and do some reading which is were much of the info posted here comes from.

When the HTHS hits around 2.6 cP and below is when an increase in wear can be seen in some engine components. Engines that specify 0W-16 and 0W-8 have unique mechanical design features that allow them to run that thin of oil. xW-20 was back speced for a lot of vehicles and it works for most applications, but again it can reduce the MOFT headroom between moving parts before wear can happen.
 
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When the HTHS hits around 2.6 cP and below is when an increase in wear can be seen in some engine components. Engines that specify 0W-16 and 0W-8 have unique mechanical design features that allow them to run that thin of oil. xW-20 was back speced for a lot of vehicles and it works for most applications, but again it can reduce the MOFT headroom between moving parts before wear can happen.
I agree with this completely. The next question is 'does it matter over the life of a vehicle?'.
Because if it mattered, we'd see failures.
And yet the data shows the opposite.
 
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I agree with this completely. The next question is 'does it matter over the life of a vehicle?'.
Because if it mattered, we'd see failures.
And yet the data shows the opposite.


The never ending argument. A 30 grade might get a engine to 300,000 miles and a 20 grade might only get it to 280,000 miles. Who will know if it was the oil?

Most vehicles are gone long before that anyway either by collision or decay or failure of other drivetrain components.
 
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I agree with this completely. The next question is 'does it matter over the life of a vehicle?'.
Because if it mattered, we'd see failures.
And yet the data shows the opposite.
There is a giant leap between "slightly more wear" and "failures". If say the bearings or rings (where HTHS matters most) wear more with thinner oil, the engine isn't going to fail, but it could have less compression, burn more oil and have a bit less power at high mileage compared to if a little thicker oil was used. That's what slightly more wear could do, but it would never make an engine "fail".

With my vehicles, if it calls for 5W-30 I run 5W-30, but it it calls for 5W-20 I also use 5W-30 because I like a bit more HTHS headroom. :)
 
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The never ending argument. A 30 grade might get a engine to 300,000 miles and a 20 grade might only get it to 280,000 miles. Who will know if it was the oil?

Most vehicles are gone long before that anyway either by collision or decay or failure of other drivetrain components.

This. I would guess vehicles are on the road longer not because they arn't having catastrophic engine failure, but because they are not disintegrating. I knew a ton of people with late 90's early 2000's GM trucks, including my parents 2000 Chevy Astro Van. All of them had perfectly good engines. It was when the brake lines, A/C lines, body's and other items started to turn to dust that people got rid of them. Oh yeah and the wonderful 4L60 that even the 4.3L Vortec could kill.

I suspect any vehicle made in the last 10 years is much better about such things. Except for Toyota trucks. They still suck :ROFLMAO: Guys on the Lexus GX group I am in will sometimes post a picture of their finger poking through a rusted out portion of the frame.
 
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There is a giant leap between "slightly more wear" and "failures". If say the bearings or rings (where HTHS matters most) wear more with thinner oil, the engine isn't going to fail, but it could have less compression, burn more oil and have a bit less power at high mileage compared to if a little thicker oil was used. That's what slightly more wear could do, but it would never make an engine "fail".
I agree with you completely.

This brings us right back to 'does it matter?' and the evidence demonstrates that it does not matter by virtue of the fact that cars on the road are older than they have ever been.

Cheers!
 
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I agree with you completely.

This brings us right back to 'does it matter?' and the evidence demonstrates that it does not matter by virtue of the fact that cars on the road are older than they have ever been.

Cheers!
Yep ... but like said before, it can matter depending on use conditions. That's the main reason some manufactures say to use a thicker oil for high load, high speed or track use ... and other countries show a whole range of acceptable oil viscosity in the OM. But the typical grocery getter won't have to worry or care. :)

Personally, I don't treat my vehicles with the thought that it might get totaled or rust out before it's worn out. If that was the case, I also wouldn't even care that much about routine maintenance and let the next guy worry about it. It certainty isn't going to hurt any car to run xW-30 over xW-20 or a xW-20 over a xW-16 if they want a bit more wear protection headroom and don't car about maybe loosing a minuscule amount of fuel economy .
 
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Yep ... but like said before, it can matter depending on use conditions. That's the main reason some manufactures say to use a thicker oil for high load, high speed or track use ... and other countries show a whole range of acceptable oil viscosity in the OM. But the typical grocery getter won't have to worry or care. :)

Personally, I don't treat my vehicles with the thought that it might get totaled or rust out before it's worn out. If that was the case, I also wouldn't even care that much about routine maintenance and let the next guy worry about it. It certainty isn't going to hurt any car to run xW-30 over xW-20 or a xW-20 over a xW-16 if they want a bit more wear protection headroom and don't car about maybe loosing a minuscule amount of fuel economy .
Or even xW-40 or xW-50. Car is nearing 160k despite being told by another member of this forum my particular engine only has a life of 150k or less. Doesn't burn a drop of oil and while I haven't performed a compression test, the Butt Dyno says it's just as good or better than it was when new.

That's not to say viscosity is the only factor in it's longevity. Very frequent oil changes, keeping the intake ports and valves clean, and using the highest octane gas possible probably helps too (the engine pings lightly on regular).
 
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