The SAE 0w-40/5w-50, "One Size Fits All" Multigrades

[TooSlick]

Perhaps I should have clarified this issue a long time ago. My issue IS NOT with the Mobil 1, 0w-40 or the Castrol Syntec 5w-50. My issue is with ALL the lubricants that carry these two grades. I simply feel that going to a 40 to 45 point spread is stretching things too thin.

For example, if you want excellent cold temp behavior and fuel efficiency, a 5w30 is a much better choice than a 5w-50. OTOH, if high temp stability in a racing situation is required, a 15w-50 or 20w-50 is going to work significantly better than the 5w-50.

In other words, you end up compromising the extreme temp performance at both ends of the temp range by trying to do too much with the same oil.

Specific to the SAE 0w-40's, I simply don't think they provide any advantage (w/ a typical HT/HS of perhaps 3.6 Cp), over the more shear stable, ACEA "A3/B4" rated, xw-30 synthetics. In fact you can make the argument that the narrow range 5w30/10w-30 oils are going to hold up better in any high performance application. This is why I like the Mobi1 1, 10w30 (particularly their new Extended Performance) over their 0w-40. It is also why I like the shear stable, 5w-40 Delvac 1 over their 0w-40 for any application requiring a mid-range 40wt product.

I hope this clarifies things a bit ....

Ted

 

[Shannow]

Would an oil group versus Viscosisty Index table help things ?

 

[TooSlick]

Shannow,

Yes I think so, since shear stability is also a function of Viscosity Index (VI) as much as SAE grade....

If the VI is too high, the oil is actually less desirable - if this VI has primarily been achieved through the use of polymeric thickeners. The price of the product is normally the best indicator of this, ie the "cheap" synthetics ($3.50-$5.00 per quart), use a higher percentage of polymer than the more expensive ones....

How do I know this???? Simply by the economics of the current raw materials (basestocks, additives) used to make multi-grade oils....

Ted

 

[Shannow]

Pretty much the first look at any data sheet I use...V.I., followed by pour point.

 

[Pablo]

I agree. 5W-40 is as far as I go....but that's interesting because there are some great 5W-40's out there!

 

[JHZR2]

quote:

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Originally posted by Shannow:
Pretty much the first look at any data sheet I use...V.I., followed by pour point.

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Can you explain more what you look for in terms of VI when reading the charts?

Thanks,

JMH

 

[ebaker]

Many high output engines need a 40 weight oil. They may also have hydraulically (engine oil) controlled variable valve lift and variable cam timing mechanisms that need 0w when cold.

 

[Dr. T]

Although I agree in theory....

I have compared/used Mobil 1 5w30, 0-40, 5-40, 15-50, Syntec 5-40 and 5-50 in the same engine.

While the 5-50 will/may not provide the same protection as a 15-50...let me tell you it's more robust than any 30 or 40 weights listed above over the approx. 7k mi. intervals that I've used it.

In other words, eg. GC may be more 'shear stable' than Syntec 5-50 due to it's smaller range, but the film thickness provided is not the same as the 5-50...even for the duration of the interval.

Likewise, the film thickness provided by an A3 lube eg. GC is more superior than any one provided by an A1 30 weight eg. Mobil 1 5w30 or 10w30 (also for the duration of the interval).

As soon as I can get my stupid engine clean/deal with consumption issues (auto-rx/LC/FP) I promise to do a used oil analysis...

 

[The_Jeff]

I run Mobil 1 0w40 in my saturn in the winter. It only "needs" a 30-weight, but burns around a quart per 600 miles-- and I'd like to reduce that. I don't particularly care if it shears down to a high 30-weight in time since it'll probably still be thicker than Mobil 1 0w30 or 5w30. My low output engine will never get hot enough to do a number on this oil.

I see temps of -20'F or worse a few times a winter. I run cheap dino during the summer (10-40 PCMO or 15w40 HDEO) and only buy the synthetic for its cold weather properties. So, Mobil 1 0w40 (and maybe GC

) are perfect in my app.

 

[ruking77]

I would also agree! I think if you could make your decisions based solely on that criteria that would be GREAT! In a weird sort of way, I miss having 5-10w30- and the same oil filter working for the five vehicles I had!


The neatest thing about that was you really only need to buy enough for the very NEXT oil change (7 quarts) and topping (1 quart max 2 quart extra)

However, unless you make a concerted effort or all your vehicles HAPPEN to require the same oil: for the past several years, it is a far different story (for me) . So for example, right now I have on hand Mobil 1s's: 0w20, 5w20, 5w30, 5w40. So as a sign of further complication, if I use the new Mobil 1 Extended Performance 5w30 or 10w30 that you think is very good, it does not meet the 4178M spec for one vehicle!!?? The other two can run 5-10w30 EP. So while I think the new EP will cover the 4178M specifications, I'd hate to be the guinea pig. So add to that inventory: 5-10w30 EP.

I also can run 0w40 in place of the Mobil 1 Truck and SUV 5w40 aka Delvac One. But essentially I have come to the same conclusion as you have. Plus a biggie for me: LESS inventory.

So far I have have gone from a high of 6 line items to (three). TOO much brain cells already! (Mobil 1 0w20, the oem took it off the market.)

[ April 21, 2005, 11:45 AM: Message edited by: ruking77 ]

 

[haley10]

It would not surprize me one bit that Amsoil is not developing and might market a 0W-40 formula in the future.

Don't shoot yourself in the foot.

 

[Jay]

Amsoil has had a 0w-40 for some time now. It's intended for 4-stroke ATVs,snowmobiles, outboard motors, and motorcycles.

I understand that some ATV manufacturers actually spec the 0w-40 grade. Anybody know why?

 

[buster]

I tend to agree with TS. However, the Esso 0w30 and 0w-40 are very shear stable (3.6 and 4.1) for both oils. They use a thicker basestock. For the North American market we will never see these oils. If they did, they would sure as **** satisfy the 6k BITOG crowd. For better or worse it's all about CAFE right now in the US.

 

[JohnBrowning]

I too like a 5W40 over the 0W40's! With that said if an affordable 5W40 was not available to me I would not have a problem with 0W40! Sure Mobil 1 0W40 does shear down to a 30Wt. in some applications but in spite of that it still puts up good numbers! I think my problem with it is that I would rather use a shear resistant 5W40 though when ever it is available!

I think that the Mobil 1 0W40 makes sense for those people that are afraid to run a true blue 40Wt. If UOA means anyting the numbers for the Mobil 1 0W40 have been great in spite of it's propencity to shear! Now I am really excited about the Mobil 1 Extended Performance 10W30 and 10W40!!! I can not wait to see what we see with these. I have really high hopes for the 10W40 especialy!

 

[G-MAN]

quote:

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Originally posted by Dr. T:
Likewise, the film thickness provided by an A3 lube eg. GC is more superior than any one provided by an A1 30 weight eg. Mobil 1 5w30 or 10w30 (also for the duration of the interval).

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Mobil 1 5w30 and 10w30 are A5 rated, which is the ACEA low HTHS extended drain spec in Europe.

 

[Patman]

What about a 0w40 like Castrol's Formula R 0w40 in Europe/Australia? It's just barely a 40wt oil, at 12.9 cst, so it's not really that big of a spread. Plus if it uses the same trick base oil which GC 0w30 uses, it is possible this 0w40 contains little to no VII in it at all.

 

[billmac]

quote:

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Originally posted by TooSlick:
I simply feel that going to a 40 to 45 point spread is stretching things too thin.

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I'm puzzled that you make that statement and then say that you like sheer stable 5w-40 Delvac 1. Based on your comments, I would have thought Amsoil Series 3000 5w30 or most any of the 15w40 diesel oils would be more to your liking. The point spread is much less. As regards the VI, The Mobil website shows the Delvac 1 to have a VI of 151 per ASTM D2270. To me this is surprisingly low compared to even some of the 15w40 diesel oils that I have reviewed including the Amsoil AME product which shows a VI of 164.

 

[427Z06]

quote:

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Originally posted by Patman:
What about a 0w40 like Castrol's Formula R 0w40 in Europe/Australia? It's just barely a 40wt oil, at 12.9 cst, so it's not really that big of a spread. Plus if it uses the same trick base oil which GC 0w30 uses, it is possible this 0w40 contains little to no VII in it at all.

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Good point, Patman. Current basestock technology would allow for a 187 VI with very little added VII. Castrol's Formula R 0w40 at VI of 178 is not that much different. Further, there's various qualities of the VII. Not all of them shear apart so easily.