Mixing oils - what viscosity do you get?

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Sorry but by that logic, Amsoil and numerous other oils are "unsafe", which we know is not necessarily the case - I'm pretty sure you're not saying that Amsoil is unsafe to use, or are you? Not trying to start a fight, but insistence on a test being passed to be safe, well, passing a test isn't possible when an oil isn't submitted or put through that test.

In any case, let's fall back to the M1 discussion and my question, which you didn't answer: if, in fact, it was unsafe to mix viscosities, then wouldn't ExxonMobil, one of the largest producers of petroleum products in the world, have put out some sort of warning by now?
I have no idea whether Amsoil tests their oils against ASTM D6922 but they better. That would constitute pretty significant negligence if they did not.

And you don’t have to be sorry, I was just stating facts. If some blender was producing an oil that failed ASTM D6922 then that would be a very bad thing. All of which is separate from performance specifications which define other things about the oil. That’s what we were talking about. You could still have two, or 10 crummy performing oils that are miscible in your “frankenbrew” example. This is where people miss the boat on miscibility as they mistake that for performance.
 
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Kuato

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I have no idea whether Amsoil tests their oils against ASTM D6922 but they better. That would constitute pretty significant negligence if they did not.

And you don’t have to be sorry, I was just stating facts. If some blender was producing an oil that failed ASTM D6922 then that would be a very bad thing. All of which is separate from performance specifications which define other things about the oil. That’s what we were talking about. You could still have two, or 10 crummy performing oils that are miscible in your “frankenbrew” example. This is where people miss the boat on miscibility as they mistake that for performance.
Ok but what are your thoughts on my Mobil1 question?
 
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The missus makes a jug of blended raw milk, wild berries & avocado about every day.
These past few years, she’s taken to adding a homemade kefir culture to it.
Neither the wild berries nor the raw milk are approved or certified, and adding kefir culture likely throws the formulation’s chemistry off.
My internal combustion unit doesn’t care, and tells me it’s safe, and exceeds the standards of any off the shelf smoothie.
 

Kuato

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Both are API licensed therefore you know they passed ASTM D6922 as part of the licensing requirements. As a result they are miscible.
A-ha. Now I finally understand what your point is. Your bringing in the test criteria alphabet soup simply muddied my oversimplified discussion.
I was going from the assumption that the oils used are mixable.

However, NOT having the standard STILL doesn't mean an oil is not miscible. It could be.
 
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So for you mixing experts. How much of an impact would and what kind of numbers would I have mixing 4.5 quarts of Amsoil Signature Series 0W 20 and 1 quart of Signature Series 0W30? Or would I see more benefit doing 3.5 qts of the 0w20 and 2qts of 0w30? Just looking for a more robust oil than plain 0W20. I have several quarts of Amsoil Signature Series in both viscosity. I really appreciate any number data.
 

Kuato

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So for you mixing experts. How much of an impact would and what kind of numbers would I have mixing 4.5 quarts of Amsoil Signature Series 0W 20 and 1 quart of Signature Series 0W30? Or would I see more benefit doing 3.5 qts of the 0w20 and 2qts of 0w30? Just looking for a more robust oil than plain 0W20. I have several quarts of Amsoil Signature Series in both viscosity. I really appreciate any number data.

Easy - just throw your numbers into Widman's calculator. At a SWAG, still a 20.

Why not grab some 0w-40 to mix with the 20? Amsoil makes a good one and it would average a 30.
 

Kuato

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Blackstone's response to my viscosity question:

If you're reading cSt, then yes it would be a little thin for 40W. SUS starts at 65, and by that metric the sample does just barely fall in the 40W range.

That said, 11.74 cSt could really be in range a number of different weights (including a slightly thick 30W or slightly thin 40W). In this case, the grades I mentioned in the report are more of what it seemed closest to based on the SUS readings.


So ... it tested right on the border of 30 and a 40 grade. Just what would be expected from averaging equal parts of a 20 and a 50.
 
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I have a mix in my crankcase now of 4 quarts of QSHM 10w40 SN PLUS and 3 quarts of Mobil Clean 5w20 SM era, oldest in my stash. A UOA should be interesting.
 
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It seems to follow that if a vehicle that specs 0W-20 is shearing a lot due to fuel dilution, one option would be to mix some 0W-30 (preferably same brand and flavor). Going 50/50 would get close to a 25 weight. Different ratios could get you, for example to the top of the 20 weight range (maybe 70/30 or 80/20). Interesting.
 
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If fuel dilution and/or mechanical shear are a problem, why not just use the 30-grade in the first place?
I'm speaking theoretically here, I'm not saying I'm going to do this. So if one wanted to stay with a 20 weight, just wanted it to be at the top of the 20 weight range, they could try a little creative mixing. If they wanted to be exact, they could do a VOA on their mixture before pouring it into the sump. I could see a scenario where doing this would keep the oil from shearing out of spec. You'd start with a 20 weight at the top of the range and end up with a 20 weight at the bottom of the range.
 
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It seems to follow that if a vehicle that specs 0W-20 is shearing a lot due to fuel dilution, one option would be to mix some 0W-30 (preferably same brand and flavor). Going 50/50 would get close to a 25 weight. Different ratios could get you, for example to the top of the 20 weight range (maybe 70/30 or 80/20). Interesting.
No it won't because there is no such thing as a 25 "weight", or grade, which is the proper term.
 
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No it won't because there is no such thing as a 25 "weight", or grade, which is the proper term.
Of course there's no such thing as a 25 grade if you want to be pedantic, but I think most people would get the point of the comment: a viscosity higher than a typical 20 grade, but lower than a typical 30 grade.
 
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The mixture in your scenario would yield either a heavy 20 or light 30. The concern with the intent is that a new member may read it as fact that a 25 is an obtainable grade.
How about "the equivalent of a theoretical 25 grade." ;)

One practical way of looking at this is if you don't want to run out of grade on your vehicle, but you want the thickest possible in-grade oil. According to Widman's calculator, you could mix 1 part 0W-30 with 4 parts of 0W-20 and end up with a 9.27 cSt (just under 9.3 J-300 standard for 20 grade). This is with using Mobil 1's advertised viscosity for their 0W-20 and 0W-30 AFE. I suppose if you wanted to be really precise, you could do a VOA of each, then use those values in the Widman calculator, then mix, THEN do a VOA of the mixture. But the idea here is to use the same brand and variety of oil, with the same winter rating, to get to the upper end of your vehicle's spec'd viscosity grade. I might actually try this on our Civic and CR-V next oil change.
 
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