You really need to take a closer look at the situation. 0W20 oil is thicker when cold and thins with heat just like all oil. And 0W20 is never as thin as water.
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I think he needs to take a closer look at Magnuson-Moss as well because he’s not clear about what that law states either.
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@ToyotaWill? More like @ToyotaWon’t, or @ToyotaTroll, because ya’ll are being trolled in a big way. There is no upside to engaging with this person.
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Just the opposite. 0W-20 is THIN when cold, then thickens when heat is applied.
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ok, again, please help me understand. Your point is that even 5w20 is too thin as an engine cools from running (‘hot’) temp to ambient (‘cold’) temp and so something like 10w30 is better. Is that correct?
If so, here’s data on 10w40 (because I don’t have 10w30 at hand), which shows kinetic viscosity INCREASING as temperature decreases from ‘hot’ (about 100C) to ‘cold’ (about 20C):
Even if the viscosity at ambient (cold) temp of 10w30 is a little different from 10w40, is your concern that that level of viscosity is necessary and so no lower level is advisable? Even though those lower viscosities would be like the same oil at higher temperatures?
Data is from Wiki | Anton Paar Wiki
Maybe you have a chart indicating the temperature/viscosity of 0W20 oil @MikeInNH. Everywhere that I look oil thins as temperature rises. Of course multi viscosity oils thin significantly less but they do thin.
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I think 0w20 alone won’t be enough for him. It will probably have to be a comparison of at least 0w20 and 5w20, with possibly 10w30 thrown in.
And the comparison will likely show some difference at ‘cold’ temps, which will be his focus.
Wow, a lot has happened here overnight. Do any of you guys sleep?
@ToyotaWill, Couple of things here. I found the sludge at 45k miles. I don’t know why I didn’t notice it earlier. There is still some contamination of oil from combustion by-products. Todays engines burn gas so efficiently that the combustion by-products have been greatly reduced.
I am not using drive cycles to determine oil changes, that would be too hard to track. The oil change monitors that many cars have use drive cycles as one of the factors they monitor. They monitor other factors as well. But for them to be accurate, you have to use the oil that meets the specs that the monitor was programmed with. The monitor cannot actually analyze your oil either for use or type.
The Moss-Magnusson Act tell manufacturers that they cannot specify that you have to use only their brand of oil or that it has to be changed at a dealership only. It does allow them to establish specifications for the oil. If you chose to use an oil that does not meet the specifications and you have an engine failure, then they must prove that the failure was caused by the oil. For example, they could not blame the oil for a broken valve spring. They still might not cover the engine if they can prove you over-reved it but they can’t blame the oil.
Beyond that, I am not going to get into the discussion of the merits of one oil over another. Your car, your money, not my business. I don’t even care how often you change your oil, I was only reporting an experience that I had. That is one data point out of millions of data points. It is not a trend or a graph or a proof of concept.
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Maybe ironic in all this is that the ‘thinness’ of 0w and 5w oils might help give longer engine life by providing better lubrication at startup (‘cold’) conditions.
And from one of the links
The latest trend in racing is to run tighter bearing clearances and use thinner oils such as 0W-20, 0W-30, 5W-20 or 5W-30 to reduce friction and drag.
So maybe even the same Toyota engine is being manufactured with tighter clearances that make sense with 0w- and 5w- oils.
Mike, all those articles are making a fundamental but very common mistake. Modern oils are NOT multi-viscosity, well they are but not in that sense. Modern oil are Multi-grade. The grade refers to a viscosity/temperature curve.
This means that multi-grade oils do not change viscosity as quickly as single grade oils do. They become a lower grade as they cool, but they do NOT become less viscous. All three of your links made this mistake.
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A chart of viscosity/temperature would be of some help here. Your links were somewhat childish in their comparisons and descriptions.
Over a wide range:
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This is a commonly misunderstood characteristic.
Here’s a great site that explains it in a very clear way-
In short-
Keep in mind that as temperature increases, the viscosity decreases. The addition of modifiers will only slow down the rate at which the viscosity decreases.
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BTW, the kinematic viscosity of water is only 1.0 cSt at 20 degC and 0.3 cSt at 100 degC.
;-]
My interpretation of these charts, just as all other charts on the subject indicate, is that every grade of oil has a decline in actual viscosity as temperature rises. There is never a brand or grade that increases in viscosity as temperature increases… Or so it seems to this primitive self educated mechanic.
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That graph is the most concise, definitive explanation of multi viscosity oil that I’ve ever seen.
And from that site
Unfortunately, viscosity index improvers do have some drawbacks. The primary disadvantage is they are susceptible to mechanical shearing. When referring to the slinky analogy, it is easy to imagine a stretched-out slinky cut in half by mechanical processes to produce two shorter slinkys.
As the additive is repeatedly sheared, it loses its ability to act as a more viscous fluid at higher temperatures. Higher molecular weight polymers make better thickeners but tend to have less resistance to mechanical shear. Lower molecular weight polymers are more shear-resistant, but do not improve viscosity as effectively at higher temperatures and, therefore, must be used in larger quantities.
So it seems that a variable weight oil like 0w40 can ‘breakdown’ to become more like 0w30 and then 0w20.
Hey I’ll be the gunea pig on our rav 4, only 1900 miles so far but if soeone has oil analysis recommendation at 10k I will send mine in.
This thread ill probably be alive in August when we get there.
@ToyotaWill not sure why your oil is so dirty at 4 to 5 k, I will keep an eye on mine.
I imagine many people are on the 10k interval with Toyotas, as like us they may have 2 years free maintenance, with oil changes at 10k.
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