Are you disappointed in the shear stability of most 5w30's?

[buster]

A common band aid for those that want to increase the margin of protection a bit by using a 30 grade over the OEM 20 grade often move to a 5w30 or even the 0w grades. However as we know, the larger the spread the more VII's which isn't a good thing, especially in a fuel diluting engine. I've seen xw-30 grades drop to a 20 in under 5k miles.

 

[Snagglefoot]

The range in kinematic viscosity of 5w30 is 9.3 to 12.7 cSt. The graph shows the viscosity drop in percentage but doesn’t show the original viscosity for each product. That information would be very useful.

 

[OVERKILL]

This is the test that forces the oil through a diesel fuel injector. I'm not sure how much applicability that has to an actual operating engine but I know SonOfJoe mentioned it at one point:

If I'm honest, as we sit here in 2017 I do think that the fear of shear is somewhat overdone. Do VIIs permanently shear? Yes, a little bit initially, but under normal driving conditions, nothing like as much as you might think. Can VIIs shear a lot? Yes, this is exactly what the European KO30 cycle shear test does but it only manages to do what it does by repeatedly blasting the oil through a fuel injector nozzle. Is anyone seriously suggesting this is representative of what happens to oil in an engine? When oils do shear, even in real life, the level of shear tends to depend on how much polymer the oil contains. The more polymer you have, the more likely you are to notice the effects of shear. So for example, shear might be very apparent in a Group I 10W40 but not particularly apparent in a Group II/II+ 5W20 oil. Finally it's worth noting the direction of travel on VIIs. OCP VIIs have sort of taken over the world and have largely displaced PMA VIIs (except in Japan) and HDS VIIs (apart from in very top-tier oils). OCPs are so much more resistant to thermally induced shear than PMA & HDS VIIs. Also, with the advent of things like dexos, VIIs are becoming more shear stable as the US moves closer to the European position. Hope this helps...

 

[Zee09]

Are you suggesting heavy 20's?
If so which are you using?

 

[buster]

This is the test that forces the oil through a diesel fuel injector. I'm not sure how much applicability that has to an actual operating engine but I know SonOfJoe mentioned it at one point:

Great information thank you OVERKILL.

 

[Oro_O]

It's the shear strength that appalls me in a 5w30, not the stability. Why not 10w30, unless you live in northern Montana?

You talk about the viscosity spread and VII's, why not get out of the mass marketing hypnosis and make the leap to good oil?

 

[buster]

Are you suggesting heavy 20's?
If so which are you using?

Not necessarily just a trend I've noticed since quite a few like to jump up to a 30 grade due to fuel dilution. Doing so however doesn't guarantee you'll end up with a 30 grade.

 

[4WD]

A common band aid for those that want to increase the margin of protection a bit by using a 30 grade over the OEM 20 grade often move to a 5w30 or even the 0w grades. However as we know, the larger the spread the more VII's which isn't a good thing, especially in a fuel diluting engine. I've seen xw-30 grades drop to a 20 in under 5k miles.

Same chart with 0w20 ?

 

[buster]

It's the shear strength that appalls me in a 5w30, not the stability. Why not 10w30, unless you live in northern Montana?

You talk about the viscosity spread and VII's, why not get out of the mass marketing hypnosis and make the leap to good oil?

10w30 is a solid grade, but so is 0w20.

 

[buster]

Same chart with 0w20 ?

I think the 0w20's are very stable.

 

[4WD]

Well … 5w30 can go cheaper on base stock and make spec … when they don’t, look at VM percentage

 

[buster]

Two of the most shear stable oils I've seen over the years are Mobil 1 ESP and Red Line.

 

[Strokenmerc]

This is the test that forces the oil through a diesel fuel injector. I'm not sure how much applicability that has to an actual operating engine but I know SonOfJoe mentioned it at one point:

This wouldn't happen to be a test result posted by Amsoil is it? Flame suit on

 

[blingo]

Disappointed with the PQIA I'd say. But people prefer just laughing at a few funny bottles each year and otherwise blame most on ten, twenty, thirty, forty, fifty or more percent of fuel rollin' up the score.

 

[PimTac]

Disappointed with the PQIA I'd say. But people prefer just laughing at a few funny bottles each year and otherwise blame most on ten, twenty, thirty, forty, fifty or more percent of fuel rollin' up the score.

Huh?

 

[Propflux01]

Not necessarily just a trend I've noticed since quite a few like to jump up to a 30 grade due to fuel dilution. Doing so however doesn't guarantee you'll end up with a 30 grade.

But does it not almost "guarantee" a heavier 20 grade? Seems go me I'd rather have that than a 20 grade that shears into a 16 grade.

 

[4WD]

But does it not almost "guarantee" a heavier 20 grade? Seems go me I'd rather have that than a 20 grade that shears into a 16 grade.

Viscosity is measured by shear stress … to me the topic is viscosity loss related to VM -vs- type of base stock.
(Amsoil SS having higher group stock in 5w30 … 0w20 having inherently better base stock)

 

[buster]

However, even the most expensive 30 grade oils crash in the presence of fuel.

https://www.civicx.com/forum/attachments/amsoil-ss-0w30-oil-analysis_5038mi-dkl-pdf.135305/

 

[nomas]

I have to wonder how some of you sleep at night .

 

[Kamele0N]

I'm not sure how much applicability that has to an actual operating engine but I know SonOfJoe mentioned it at one point:

. Also, with the advent of things like dexos, VIIs are becoming more shear stable as the US moves closer to the European position. Hope this helps.

With other words....stay away from API/ILSAC oils