Don't Understand Why Folks Are Splitting Hairs...

[OldCowboy]

over various xxW oils.

For example, in a recent post someone said they would use Mobil 1 5w30 but not 0w30 because the 0w30 was too thin. Now the Motor Oil University tells us that 30 weight is 30 weight, regardless of the xxW in front of it. So, I checked out the PDSs on three Mobil 1 30 weight oils and here's what I found:

Code:


Test Mobil 1 Advanced Fuel Economy 0w30 Mobil 1 5W30 Mobil 1 10W30



Viscosity @ 100*C 10.9 11 10.1

Viscosity @ 40*C 62.9 61.7 63.2

Viscosity Index 166 172 146

HT/HS Viscosity 3.0 3.1 3.0


It appears to me that once these oils get to operating temp, there's not enough difference between them to quibble over. While the 0W will give better viscosity in the cold, if you live where the ambient temps routinely hit 104*F (40*C), there is again not enough cold start difference to quibble over.

 

[garlicbreadman]

this forum makes people over think everything...

 

[Dominic]

I agree Cowboy. Small differences in oil viscosity at a given temperature tell you very little about the oil itself. I'm sure this is why they describe most car oils in more vague terms like SAE 30 or 40 weight. Even those oils you posted all slow a very similar HTHS, making the differences meaningless.

Makes you wonder what makes the "AFE" so advanced in terms of fuel-economy, or if it's simply a marketing gimmick?

 

[bepperb]

You're absolutely right.

But you can't get in an argument with people about stopping arguing.

Note the 5-30 is thicker than the 10-30 at operating temp.

Also note the 0-30 has a lower VI than the 5-30.

The assumptions people make when recommending one over the other are often incorrect (high VI of 0w-xx is a problem, or 5-30 is too thin at temp).

 

[ARCOgraphite]

Ha the 5w30 has a better VI than the 0w. 0W rated oils dont have any advantage in starting above -10deg, viscosity wise. Ow/5w/10w is also pretty meaningless above freezing. WINTER RATING HAS nothing to do with operating viscosity, whatsoever.

 

[Jim Allen]

Also bear in mind the cold cranking tests, MRV or CCS, which will show the 0x oils in a slightly better light vs 5x or 10x. Unfortunately, they don't always list them in the dat sheets.

 

[Eddie]

Or, some of us don't have our life priorities correct.

 

[Artem]

Originally Posted By: garlicbreadman
this forum makes people over think everything...


That is SO true. We over think motor oil WAAAAAY to much, myself included. Oh well.

Originally Posted By: Dominic


Makes you wonder what makes the "AFE" so advanced in terms of fuel-economy, or if it's simply a marketing gimmick?


I saw its marketing gimmick with the 0w part making the average Joe think the oil is thinner or whatnot.

 

[daves87rs]

Some good points here...

 

[Skid]

The high mileage formulations are significantly heavier (and have more ZDDP).

5w30
69.2 @ 40 C
11.7 @ 100 C
3.3 HTHS

10W30
78.1 @40 C
12 @100 C
3.5 HTHS

 

[FZ1]

Why is the VI on the 10-30 less than the VI on the other 30 weight oils?

 

[gulian]

I also agree, of all the oils I've used, and all the different grades and brands and ratings the only thing I've ever noticed is a slight oil usage of M1 in my z24 and gtx in a motorbike. Regular maintenance is the important part.

 

[tmorris1]

Originally Posted By: garlicbreadman
this forum makes people over think everything...

Yep, this whole forum wouldn't exist if people didn't split hairs.

 

[OldCowboy]

Originally Posted By: FZ1
Why is the VI on the 10-30 less than the VI on the other 30 weight oils?


It's a bigger stretch between 0W (6200 @-35*C) and 5W (6600 @-30*C) and 30 (9.3-12.5 @ 100*C) than it is between 10W (7000 @-25*C) and 30. This requires an oil with a higher Viscosity Index.

 

[HTSS_TR]

If the PDS's of the three M1 30 grade oils are accurate then 5W30 is a better choice for drivers whose winter temperature never below freezing such as Coastal California or South Florida, no reason to use 0W30.

 

[Steve S]

The .1 makes all the difference in the world.

 

[Steve S]

Originally Posted By: OldCowboy
Originally Posted By: FZ1
Why is the VI on the 10-30 less than the VI on the other 30 weight oils?


It's a bigger stretch between 0W (6200 @-35*C) and 5W (6600 @-30*C) and 30 (9.3-12.5 @ 100*C) than it is between 10W (7000 @-25*C) and 30. This requires an oil with a higher Viscosity Index.
or more viscosity improvers.

 

[dparm]

I'd use whichever of those two is on sale.

AFAIK the AFE blend is "newer" and might have a "better" add pack but again, splitting hairs.

 

[robertcope]

I believe the AFE used to be considerably thinner than the 5w30. The SN formulations have really mixed things up in that reagard. If I recall, the 5w30 EP is even thinner now... may be remembering incorrectly, though...

robert

 

[steve20]

"""0W rated oils dont have any advantage in starting above -10deg"""


The -10 degree portion of the quote: Is this a known fact I missed, or some backyard wisdom?