How shear-stable is M1 0W40?

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RPMster

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Hoping to hear from those who have experience with M1 0W40 and follow the "normal driving conditions" interval in their owner's manual -- or -- extend out to 10,000+ miles.

A few questions regarding the shear-stability of this oil:

1) Before or after using M1 0W40, had you used a synthetic 30 weight? After a full OCI, did you notice any big differences in viscosity either visually (runniness/thickness on dipstick, consumption, etc), or in UOA comparisons?

2) Does the oil seem to hold up well to fuel dilution from lots of short-tripping, or from Direct Injection, or both? (again, either visually or by UOA numbers)

3) For those who have done UOA's on this oil, how much did it shear and in what vehicle/driving conditions?
 
It'as a shear stable as it needs to be. More shear stable than the previous SM version. They bumped it up a bit.

2. Yes
 
I ran it for 8,800 miles in wife's C300. It was a mix of hwy and city driving over a 12-month period. 100C viscosity was 12.24 cSt. This was the previous SM version... I can't remember what the starting viscosity was of that one.
 
Very shear stable. It's on the light side of 40... After 9,000 miles in a turbo engine, it was still on the light side of 40...

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2982174#Post2982174

Great oil.

In answer to your questions, the car has only had M1 0w40. Nothing else in its entire life.

The car doesn't see much short tripping, but the engine puts out quite a bit of HP, and about 590 lbft of torque...

It held right at new viscosity after 9,000 miles. There was zero oil consumption in those 9,000 miles. The UOA has more details.
 
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Originally Posted By: Quattro Pete
Originally Posted By: Astro14
After 9,000 miles in a turbo engine, it was still on the light side of 40...

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2982174#Post2982174


11.5 cSt is not a light side of 40. It's 30. Not that it's a condemning factor or anything.


Thought the line for a 40 was at 11.6, so it was right on the line, but I might be off in that definition.

That was the older M1...so it was about 12.5 cST new IIRC....and shearing to 11.5 over that length of time in a very high HP engine shows good stability, doesn't it?

The newer M1 starts out closer to 13.5, so with similar results, it would still be on the fine line of a 40...

Either way, the oil held up extremely well in my engine....and at $22.47/gallon at WM...my car will get only M1 0w40...
 
Problem with the perception that this thread (I believe) started out with is that if a 40 drops 5-6%, people on this board are all over it like white on rice. 6% on a 20, and it's shear proof...particularly as there's now lower grade for it to "have sheared to"when it's a 20.
 
Originally Posted By: Astro14
Thought the line for a 40 was at 11.6, so it was right on the line, but I might be off in that definition.

The cross between a 30 and a 40 is at 12.5 cSt:
http://www.widman.biz/English/Tables/J300.html


Quote:

That was the older M1...so it was about 12.5 cST new IIRC....and shearing to 11.5 over that length of time in a very high HP engine shows good stability, doesn't it?

The old API SM formulation had a starting viscosity of 14, so you dropped about 18%. Still, not the end of the world, IMO.
 
Originally Posted By: Shannow
Problem with the perception that this thread (I believe) started out with is that if a 40 drops 5-6%, people on this board are all over it like white on rice. 6% on a 20, and it's shear proof...particularly as there's now lower grade for it to "have sheared to"when it's a 20.


+1. Here, here and all that noise. F yeah!
 
I've got a few UOA's on it:

In my M5, in the winter (note the fuel dilution):

M5UOA01January2013.jpg


I also ran it in the Expedition and it didn't shear at all, so the shear seems to be application dependant.

Both of the runs were the SM flavour, as I haven't found the SN version in Canada yet.
 
My whole mission here is to find a stout syn 40 weight that will hold up well in 8,000+ miles of short tripping (5 miles max per trip) that, at times, includes some high-RPM city driving. The owner's manual specs 5W20, 5W30, and 10W30. I've seen plenty of UOA's (including my own) where 30 weight synthetics sheared down to a 20 range.

So, would it be safe to say that M1 0W40 should end up in the mid-30 range, at the thinnest?

(with the exception of doing a few dozen 1/4 mile runs with a high-strung engine, of course)
 
Originally Posted By: RPMster
My whole mission here is to find a stout syn 40 weight that will hold up well in 8,000+ miles of short tripping (5 miles max per trip) that, at times, includes some high-RPM city driving. The owner's manual specs 5W20, 5W30, and 10W30. I've seen plenty of UOA's (including my own) where 30 weight synthetics sheared down to a 20 range.

So, would it be safe to say that M1 0W40 should end up in the mid-30 range, at the thinnest?

(with the exception of doing a few dozen 1/4 mile runs with a high-strung engine, of course)


When the owner manual states say a 30-grade oil, the manufacturer firmly understands that at some point the oil may shear down to a thick 20-grade. They wouldn't have recommended 30-grade if this was not ok with them. Considering that either 20 or 30 grade was recommended, I think it's overkill to go for a 40-grade. For a long interval, just get nice a 30-grade synthetic oil, like PU or M1 EP. If you want to get creative look up the "CATERHAM blend". It's a mix of Mobil 1 0W40 and Toyota 0W20 that achieves a 30-grade viscosity with a viscosity index higher than any 30-grade oil you can buy off the shelf, while retaining all the good qualities of Mobil 1 0W20 and Toyota's oil.
 
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PU 10w-30 is pretty stable, and would be fine in SoCal temps. If your local WM carries it that is.

What car and how many miles?
 
I'm sure this is a stupid question from an oil guru perspective, but how do you know if you have the "SN" flavor of this oil? I just bought some of this oil in hopes of reducing some consumption, and the bottles say it meets or exceeds API SN, SM, SL. I'm assuming that means it's an SN oil. Would that be correct?
 
Originally Posted By: BTC
I'm sure this is a stupid question from an oil guru perspective, but how do you know if you have the "SN" flavor of this oil? I just bought some of this oil in hopes of reducing some consumption, and the bottles say it meets or exceeds API SN, SM, SL. I'm assuming that means it's an SN oil. Would that be correct?


Yes it would.
 
Originally Posted By: KCJeep
Originally Posted By: BTC
I'm sure this is a stupid question from an oil guru perspective, but how do you know if you have the "SN" flavor of this oil? I just bought some of this oil in hopes of reducing some consumption, and the bottles say it meets or exceeds API SN, SM, SL. I'm assuming that means it's an SN oil. Would that be correct?


Yes it would.


Thank you. I also drive the WJ Grand, but I've got the big boy 4.7
 
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