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#4525710 - 09/25/17 11:56 AM Do ALL engines shear oil?
Speak2Mountain Offline


Registered: 04/07/17
Posts: 346
Loc: Mississippi
My DI 2.5 V6 from Toyota sheared PP 5w30 to 20 in 3100 miles, according to Blackstone Labs.

Blackstone also reported: 98% of add pack still left and could prolly go to 5K easily

Sidenote: got the UOA done @ 3100 miles b/c I swear I smelled gasoline in the oil. Blackstone poo-poo that one too.

PP is a strong oil


Edited by Speak2Mountain (09/25/17 11:59 AM)

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#4525734 - 09/25/17 12:23 PM Re: Do ALL engines shear oil? [Re: Speak2Mountain]
TheOilWizard Offline


Registered: 06/02/16
Posts: 105
Loc: US
Some engines are just better at it than others. The Nissan QR25DE is also known for shearing.

But we've all seen really long runs where the oil stays in the viscosity range. Driving conditions also play a role.

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#4525738 - 09/25/17 12:29 PM Re: Do ALL engines shear oil? [Re: Speak2Mountain]
Dorian Offline


Registered: 12/07/15
Posts: 300
Loc: Ohio
The 4GR-FSE is only direct injected. So the issues of oil dilution apply here. If the oil is thin and you smell fuel in it, what did blackstone say your fuel % was?
_________________________
99 Camry 5S M1 AFE 0W30 194K
14.5 Camry SE 2AR 0W20 M1 AFE 36K (Mom's)
98 Chevy Prizm 1ZZ M1 AFE 0W30 146K (Brother's)

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#4525739 - 09/25/17 12:29 PM Re: Do ALL engines shear oil? [Re: Speak2Mountain]
bigj_16 Offline


Registered: 07/03/17
Posts: 1267
Loc: Douglas County, Colorado
Originally Posted By: Speak2Mountain
My DI 2.5 V6 from Toyota sheared PP 5w30 to 20 in 3100 miles, according to Blackstone Labs.

Blackstone also reported: 98% of add pack still left and could prolly go to 5K easily

Sidenote: got the UOA done @ 3100 miles b/c I swear I smelled gasoline in the oil. Blackstone poo-poo that one too.

PP is a strong oil
Can you post the UOA? Usually Blackstone will put "TR" or "<.5%" or the actual level. If it is "<.05", you can probably smell it, and it is still dilution. Your oil probably diluted and sheared.

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#4525751 - 09/25/17 12:41 PM Re: Do ALL engines shear oil? [Re: Speak2Mountain]
TheOilWizard Offline


Registered: 06/02/16
Posts: 105
Loc: US
Is shearing out of grade possible at less than 5k without fuel dilution?


Edited by TheOilWizard (09/25/17 12:41 PM)

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#4525754 - 09/25/17 12:45 PM Re: Do ALL engines shear oil? [Re: Speak2Mountain]
Solarent Offline


Registered: 10/24/11
Posts: 945
Loc: Toronto ON
In a direct answer to your question. Yes all engines shear oil.

It is a common misunderstanding on this board and other places what is meant when we talk about oil shearing. Most people think of cutting up molecules and making the oil thinner. That is not what is meant. This is why we tried to address this in the revisions to the Motor Oil University section on the main page (see section 103)

In physics, "Shear forces" are what happens when two surfaces move past one another. When those surfaces are separated by a liquid (like engine oil) it is said that the oil is “shearing” - this does not mean the oil is breaking down or being cut up, it means that the viscosity is changing to allow more flow when the shear forces are high. When the two surfaces move past one another the directional shear force increases or decreases based on the fluid viscosity, temperature, load and speed. Incidentally these same factors are used when discussing the coefficient of friction described by tribologists as explained by the Stribeck curve.

Because all engines have moving parts, they all have shear forces that act on the oil. This is a good thing.

To understand the impact of shearing on engine oil, think about these 2 examples:
Ketchup - When you turn the bottle upside down, the ketchup doesn’t like to move. In order for it to flow, you give it a shake and apply some shear forces to it. The ketchup then “shears down” to a level which allows it to flow out of the bottle. Your engine oil also works the same way, when high shear forces are applied your engine oil also thins out. This is an example of a shear thinning fluid.

Cornstarch in water - With this mixture, when you increase the shear force (for example by hitting it with a mallet) the fluid thickens and becomes solid. It then thins out again when the shear forces are taken away. This is an example of a shear thinning fluid.

In engine oil, there are examples of when you would want an oil to either be thinner or thicker under load (or under a shear force) than when it is at rest. When passing through tight spaces or heavily loaded bearings (like on a cam shaft) if the oil is too thin, it won't keep the metal parts separated, if it is too thick, then energy efficiency is lost and you could end up with hot spots because the oil is not able to transfer heat away properly until it thins out more.

Viscosity modifiers are used to alter the way the lubricant flows under various shearing conditions. In high shear environments the oil may behave in one way, while in low shear environments it will behave a different way. The same is true under various temperature conditions. High temperature and high shear conditions are among the most severe from a viscosity perspective, which is why engine oil grades have a minimum HTHS viscosity set. Lower HTHS can produce fuel economy gains but must be balanced with additional performance to provide the same level of protection. Fortunately there are chemical engineers who specialize in Rheology who assist formulators in solving these complex issues.

In service most engine oils will temporarily "shear down" or reduce their viscosity when put under shear pressure and then return to their original viscosity when the oil moves to a different part of the engine where the shear forces are lower. This is a desirable trait as it allows the oil to maintain the proper viscosity under a wide variety of conditions that occur in the engine.

---

Coming back to your UOA testing. Your oil has lost viscosity and fallen out of grade. There are several reasons that could cause this: perhaps the oil has become diluted with a thinner material (ie fuel dilution), or perhaps the viscosity modifiers have changed in service - the molecules (polymer chains) may have been put under so much shear force that parts of the chain has become un-linked. This makes the molecules smaller and reduces their "thickening power" on the base oil mixture they are being used with - sometimes this is called permanent shear or shearing out of grade. Those are the two most common causes of permanent viscosity loss in service.

If left too long, oil can actually thicken as well. Thickening of the oil (an increase in viscosity) can result from the lighter fractions of the oil “evaporating” or “volatizing” at high temperatures. Most base oils are mixtures of both low viscosity and higher viscosity oils. It is the lower viscosity oils that have a tendency to evaporate and leave behind the higher viscosity oils with oxidation by-products, thus causing thickening of the engine oil over time.

Sorry for the long response, but I hope it helps you understand that shearing a good thing. For more information - go and read Motor Oil University, the revised version is much more informative and had the input of some really smart people from BITOG.


Edited by Solarent (09/25/17 12:52 PM)

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#4525756 - 09/25/17 12:48 PM Re: Do ALL engines shear oil? [Re: Speak2Mountain]
FordCapriDriver Offline


Registered: 10/22/15
Posts: 2376
Loc: Balearic Islands , Spain
Yes, to varying degrees is a short answer.
_________________________
1975 Ford Capri II Ghia 3000 V6, - Valvoline VR1 20W-50
1988 Ford Escort MkIV 1.6 Xr3i Cabrio, - Shell Rimula R4X 15W-40 HDEO.

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#4525761 - 09/25/17 12:54 PM Re: Do ALL engines shear oil? [Re: Speak2Mountain]
bigj_16 Offline


Registered: 07/03/17
Posts: 1267
Loc: Douglas County, Colorado
I think for general use on this board. most people understand that "shear" stands in for permanent viscosity loss. Temporary viscosity loss in this usage is not the issue, although they can be related, in some circumstances.
Her is an Oronite piece on this:
https://www.oronite.com/paratone/shearloss.aspx

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#4525764 - 09/25/17 12:56 PM Re: Do ALL engines shear oil? [Re: Speak2Mountain]
kschachn Offline


Registered: 12/26/05
Posts: 9367
Loc: Upper Midwest
Actually oil never shears, correct? I don't see how you could break apart relatively short hydrocarbon molecules. I would think the short answer is that no engine shears oil but it may affect the viscosity modifiers. An oil without modifiers will not exhibit viscosity loss due to mechanical shear.

And to make it worse, nearly all the oil analysis we see on here (especially from Blackstone) have shown that they are unreliable at distinguishing between fuel dilution and actual shearing of viscosity modifiers. Even their ability to measure viscosity seems suspect.
_________________________
1994 BMW 530i, 227K
1996 Honda Accord, 262K
1999 Toyota Sienna, 394K
2000 Toyota ECHO, 267K

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#4525774 - 09/25/17 01:07 PM Re: Do ALL engines shear oil? [Re: kschachn]
Solarent Offline


Registered: 10/24/11
Posts: 945
Loc: Toronto ON
Originally Posted By: kschachn
Actually oil never shears, correct? I don't see how you could break apart relatively short hydrocarbon molecules. I would think the short answer is that no engine shears oil but it may affect the viscosity modifiers. An oil without modifiers will not exhibit viscosity loss due to mechanical shear.


Who is using a monograde oil in the modern engine? I don't know anyone that does. OEM's certainly never recommend them. Far and away people are using multi-grade oils and that means they are using viscosity modifiers. I have yet to see a multigrade engine oil formula that doesn't contain them.

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#4525781 - 09/25/17 01:15 PM Re: Do ALL engines shear oil? [Re: Solarent]
kschachn Offline


Registered: 12/26/05
Posts: 9367
Loc: Upper Midwest
Originally Posted By: Solarent
Who is using a monograde oil in the modern engine? I don't know anyone that does. OEM's certainly never recommend them. Far and away people are using multi-grade oils and that means they are using viscosity modifiers. I have yet to see a multigrade engine oil formula that doesn't contain them.

No clue, and I wasn't advocating that anyone do so. I certainly don't. But the question was "Do ALL engines shear oil?" and my response was specific to that question, noting that it isn't the oil that is shearing.

Are all viscosity modifiers equally prone to mechanical shearing or are some better or worse than others? Does this translate into one fully-formulated oil having better or worse viscosity stability due to mechanical shear? Does the presence of fuel affect the stability of viscosity modifiers?

Do Reline and Amsoil 10W-30 contain viscosity modifiers?
_________________________
1994 BMW 530i, 227K
1996 Honda Accord, 262K
1999 Toyota Sienna, 394K
2000 Toyota ECHO, 267K

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#4525782 - 09/25/17 01:16 PM Re: Do ALL engines shear oil? [Re: Speak2Mountain]
demarpaint Offline


Registered: 07/03/05
Posts: 29734
Loc: NY
No, not in my case I have two UOA's for the same vehicle were both times the oil moved up a grade.One case was in 5K miles, the other in 6K miles. It did well in the application both times but "thickened." So saying All engines shear oil would be incorrect. There are other examples of oil "thickening" scattered about the UOA section.
_________________________
God Bless Our Troops


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#4525783 - 09/25/17 01:17 PM Re: Do ALL engines shear oil? [Re: Speak2Mountain]
FZ1 Offline


Registered: 02/07/08
Posts: 4727
Loc: Texas
You did smell gas in the oil. Those of us with fuel dilution can smell gas on the dip stick. I think we need to think about extracting the oil fill when it seems to lose viscosity so the engine maintains the spec'd viscosity.

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#4525786 - 09/25/17 01:21 PM Re: Do ALL engines shear oil? [Re: Dorian]
Speak2Mountain Offline


Registered: 04/07/17
Posts: 346
Loc: Mississippi
2%

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#4525788 - 09/25/17 01:23 PM Re: Do ALL engines shear oil? [Re: bigj_16]
Speak2Mountain Offline


Registered: 04/07/17
Posts: 346
Loc: Mississippi
yes it was at 2.0%

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