SHEAR is the reason...of course Mobil won't admit that. But you can see it somewhat by looking at the HTHS numbers, now that that have them posted.
manual says 10w-30 or 5w-30. can i use 0w-30?
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If you mean shear is the reason the 0w30 delivers better gas mileage, as in it shears down in viscosity, which results in less viscous drag and better mileage, I respectfully submit that you are wrong. In the SAE paper by Mobil engineers (which has been mentioned on here numerous times), the 0w30 grade was the most shear stable of all the Mobil 1 grades.
All the Mobil 1 Xw30 grades are either A3 or A5 rated, which means they MUST be "stay in grade" under the ACEA shear tests. That the HTHS numbers are somewhat lower than other brands merely reflects that they have a somewhat lower vis at 100*C.
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I find it very hard to believe that 0w30 Mobil 1 is more shear stable than their 10w30.
It does seem counterintuitive, I know. But that's what the paper says. And despite the persistent rumors that Mobil 1 "always" shears out of grade, the more recent UOAs of Mobil 1 have shown this not to be the case. The LS1 5w30 test has shown absolutely NO shearing loss. In those cases where Mobil 1 has been shown to shear down, I would submit that they are isolated and ANY oil would have sheared under similar conditions.
Given that the 0wXX grades of Mobil 1 could be (and probably are) blended so as to attain the vis spread and VI primarily with the base oils used, it's quite plausible that they could be more shear stable than the other Xw30 grades.
If you look at the M1 0w-30 reports on the board you won't see any shearing there either. If your car doesn't burn this oil there's no reason to use any other M1 30-weight.
Also, my gas mileage improvement showed up on the highway not around town. It was a small improvement, from 35mpg to 37mpg, but noticeable. Maybe a difference in HTHS of .1 would account for this. Maybe the basestocks in the 0w-30 have a lower coefficient of friction than the 5w-30. I agree that Mobil's explanation doesn't quite work.
[ April 18, 2003, 11:00 AM: Message edited by: Jay ]
Also, my gas mileage improvement showed up on the highway not around town. It was a small improvement, from 35mpg to 37mpg, but noticeable. Maybe a difference in HTHS of .1 would account for this. Maybe the basestocks in the 0w-30 have a lower coefficient of friction than the 5w-30. I agree that Mobil's explanation doesn't quite work.
[ April 18, 2003, 11:00 AM: Message edited by: Jay ]
Jason, your response that the reason Mobil 1 0w30 gives the best gas mileage of any Mobil 1 was one word: SHEAR. This would indicate that you think the 0w30 shears in ALL applicatons, hence it gives better gas mileage in ALL situations. I was merely pointing out that your reasoning is flawed. There is plenty of evidence that any grade of Mobil 1 will shear in some applications, and that is true of any oil. But there is NO evidence that Mobil 1 shears out of grade in EVERY application.
WRONG! For one a large, low revving, OHV V8 engine probably wouldn't shear a dino 5w60.
Secondly if you think any oil will shear under conditions M1 will shear you are even more wrong. I was able to shear M1 out of grade, nearly 2 grades. But Red Line did't even budge more than a few tenths of a cSt.
If you want an even easier example try it in a Toyota V6. It will shear almost eveything. Try your beloved 0w30 in one and see what happens to it. They sheared Amsoil 0w30 quite nicely.
Well I would not say every oil if I were you.
And I didn't say that M1 shears out of grade in every application. Nor do I believe that. NOR do I believe that the reason 0w30 has higher economy because it shears out of grade(although it may). It can still shear without doing that. The fact that the HTHS is lower plainly shows that it gives a thinner hydrodynamic film under high load, i.e. less viscous drag, i.e. better economy.
I'm also not saying that it will necessarily cause a problem for most of the motoring public, but you can't deny the basic principle behind it. It is just not something I would want.
[ April 21, 2003, 11:36 AM: Message edited by: Jason Troxell ]
And I didn't say that M1 shears out of grade in every application. Nor do I believe that. NOR do I believe that the reason 0w30 has higher economy because it shears out of grade(although it may). It can still shear without doing that. The fact that the HTHS is lower plainly shows that it gives a thinner hydrodynamic film under high load, i.e. less viscous drag, i.e. better economy.
I'm also not saying that it will necessarily cause a problem for most of the motoring public, but you can't deny the basic principle behind it. It is just not something I would want.
[ April 21, 2003, 11:36 AM: Message edited by: Jason Troxell ]
The improvement in fuel economy comes from cold temp/warm-up viscosity. ie. when the car is first started, a 0 oil is thinner than a 5, 10 or anything else. This is where you will see the improvement.
For eg. when I switched to 15-50 and the temps dropped, the fuel economy during short-trips went waaaaaay down. This is because at low temps, a 15 is molasses compared to a 10, 5 or especially a 0.
For eg. when I switched to 15-50 and the temps dropped, the fuel economy during short-trips went waaaaaay down. This is because at low temps, a 15 is molasses compared to a 10, 5 or especially a 0.
wow, nice stereotypical view of "oceanside." yes we have our surfers here but, they are just a small, small subculture. if anything, gangs and drive-by shootings have been a problem in oceanside. we also have a lot of street racers. low riders, street racers, gang bangers, surfers, skaters, gothic, rockers, ravers, etc. oceanside isn't as "beautiful" as the name sounds.
Temperature doesn't really matter when you are talking a high quality synthetic.
I ran the Amsoil Series 2000 0w30 when I lived in El Paso for over 2 years.
With the 0w30 you should see some improvement in fuel economy as the engine doesn't have to work as hard when it's cold. I would guess that you do shut the engine off occasionally?
0w30 will work fine in any area of the USA, or the world for that matter.
I ran the Amsoil Series 2000 0w30 when I lived in El Paso for over 2 years.
With the 0w30 you should see some improvement in fuel economy as the engine doesn't have to work as hard when it's cold. I would guess that you do shut the engine off occasionally?
0w30 will work fine in any area of the USA, or the world for that matter.
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