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mobil 1 0w-20 vs 0w-30 ??

Discussion in 'Gen II Prius Care, Maintenance and Troubleshooting' started by strider5, Mar 14, 2008.

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  1. strider5

    strider5 New Member

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    I was just in walmart hoping to find 0w-20, but they didnt have it. they do have 0w-30 that they are billing as a low-friction formula with the same protection as 5w-30 and 2% boost in gas mileage.

    5 quart bottle is $21.87. hard to beat that when the 0w-20 is like $7-8 per quart.

    would 0w-20 really be worth the extra coin?
  2. jayman

    jayman Senior Member

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    Around here all the Mobil 1 grades (0W-30, 0W-30, 0W-40, etc) are the same exact price. Only the Extended Performance costs more, and I really don't see what you gain from that stuff

    For example, if you want "better" protection. Mobil 1 10W-30 meets the tougher ACEA A1/A5 and B1/B5, the 0W-20 and 0W-30 do not. Mobil 1 0W-40 meet the toughest ACEA A3, B3/B4 specs, the other M1 oils do not

    I personally use Mobil 1 0W-20 year round in my Prius. Our winters can dip to -40, and I want the proven low temp performance. I've had good used oil lab results running the 0W-20 to 16,000 km

    Recently, Mobil decided to start publishing MRV data on their M1 products. About time. Although the 0W-20, 0W-30, and 0W-40 are all rated SAE "0W" to have a MRV BPT (60,000 cP) of -40, there are very apparent differences in low temp pumping

    The 0W-20 is rated for a MRV of 5,642 cP at -40. The 0W-30 is rated for a MRV of 11,100 cP at -40. The 0W-40 is rated for a MRV of 26,242 cP at -40. THe SAE limit is 60,000 cP, although the US military considers the much more conservative limit of 30,000 cP (THe former SAE limit until oil companies whined about it) a much safer bet for their MIL-L-46167 rated Arctic oils

    You should be fine with the Mobil 1 0W-30. I've used it before and it holds up very well
  3. jayman

    jayman Senior Member

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    I would take that with a grain of salt. I use the 0W-20 year round, and compared to the 0W-30, only noticed a minor difference at temps of -30 C or colder.

    A lot of claims of fuel economy improvement are based on comparison to the API Reference Oil, which is a 15W-40
  4. strider5

    strider5 New Member

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    definitely. I was mainly looking for the difference between the 0w20 and 0w30 since I can only get the 0w30 cheap. who knows, maybe walmart will start carrying the 5qt 0w20 too :D
  5. jayman

    jayman Senior Member

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    There are obvious advantages to using the 0W-20 in temps below -20 F. The 0W-30 will work well for you

    I keep careful log of fuel consumption, from Spring to Fall there is no readily apparent difference in fuel consumption between the 0W-20 and 0W-30.
  6. Rest

    Rest Active Member

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    If you are under warranty be warned Toyota will not cover the engine should there be a problem and they find out you used a 0W oil. It is not approved for the newer model Prius. At least not in the States.
  7. NoMoShocks

    NoMoShocks Electrical Engineer

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    Why not use the 5W-20 recommended by Toyota?

    Does Mobile1 have that combination?

    Since these are multi viscosity oils, if you get a larger range like 0W-30, it seems to me you will end up with a smaller percentage of the total volume of oil being in the recommended optimal 5W-20 range.
  8. strider5

    strider5 New Member

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    I would much rather use a superior synthetic over the garbage they use at the dealer. they can *say* whatever they want about the warranty, but in practice they would need to prove I improperly maintained my car. using a *better* oil would make that case pretty tough.
  9. jayman

    jayman Senior Member

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    What does the "0W" have to do with that? Say you run Mobil 1 0W-30. How is that "bad" compared to Mobil 1 5W-30. According to Mobil's own test data, the 0W-30 and 5W-30 have virtually the same operating temp viscosity.

    Even the HTHS is only very slightly different. The 0W-30 offers 2.99 milliPascals at +150 C. The 5W-30 offers 3.09 mPa s. If we were comparing 2.99 to, say, 3.75, that would be a difference.

    Toyota specs different viscosity for different markets, for the same motor. I find that very interesting, don't you? The Japan market Prius has a range of viscosity from 0W-20 to 10W-30. I doubt creeping through Tokyo traffic is easy on a motor, I've been there. Must be brutal for a motor stuck in traffic like that

    The Prius in the EU has a viscosity range - depending on ambient temps - of 5W-30 up to 20W-50. A 0W-40 is also a popular choice in the EU and I'm sure some Prius owners use it, perhaps the Toyota dealer will fill with it

    There is also a difference in oil change interval. Here in North America: every 6 months or 5,000 miles. The Prius in the EU is every 12 months or 10,000 miles

    I would like to see Toyota deny a warranty claim because a driver ran a 0W-30, or 0W-20 for that matter, instead of 5W-30. Plenty of dealership and qwikee loob places use bulk lube systems filled with crap no-name oil that are contaminated. Wonder how that affects the motor?
  10. jayman

    jayman Senior Member

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    I would like to clear up some misconceptions. First, please find attached an Adobe pdf, a TSB from Toyota regarding oil viscosity. The Prius is *not* on the approved list for either 5W-20 or 0W-20

    I'm unsure what you mean about the oil having a "smaller percentage of the total volume being in the recommended optimal ... sic"

    The SAE has a publication called the SAE J300. This is a global standard for viscosity in motor oils, and is pretty specific. I won't get into huge detail, but will try to explain a bit

    Any oil labeled "30" - which include SAE 30, 5W-30, 0W-30, and 10W-30 - must, MUST, test at 9.3-12.5 cSt (CentiStokes) at +100 C. No exceptions. This is for "fresh" oil, not oil used for awhile in service

    For any "30" oil, the minimum HTHS (High Temp High Shear) value is 2.9 mPa s at +150 C. There isn't an explicit upper limit, most "30" oils test at around 3.3-3.5 mPa S

    A multigrade that has a "W" is subject to a different test. The test mandates the maximum cold temp pumping temp where the pumping viscosity reaches the "yield stress" of 60,000 cP (CentiPoise).

    An important note: at one time, the yield stress was set at one half the limit now used: 30,000 cP. Lot of whining by the oil companies allowed the limit to be raised. The exception in US Military "Arctic" rated oil, MIL-L-46167. They still cutoff at 30,000 cP

    A "0W" oil must not exceed the yield stress at -40 C. A "5W" must not exceed the yield stress at -35 C. A "10W" must not exceed yield at -30 C. Again, these values are for "virgin" oil. Once in use, an oil can dramatically thicken

    A lot of "conventional" motor oils make heavy use of polymeric compounds to achieve the desired test results. There are a few problems with that. Most importantly, these polymers can shear down. Your 5W-30 might shear to a 5W-20.

    The polymers can also cause problems at the other temp extreme, near the borderline pumping temp. There was a lot of issues with Cold Gellation around 18 years ago, when overhead cams first became widespread. Once a conventional oil is used a bit, it can very dramatically thicken in cold temps

    I still cannot quite understand what you mean by "volume." The Mobil 1 0W-30 and 5W-30 test out virtually identical at high temps. The biggest difference is extreme low temps, where the 0W-30 has a big edge. A choice of the 5W-30 or 0W-30, why would anybody pick the 5W-30?

    Much like comparing Mobil 1 5W-20 to Mobil 1 0W-20. Why would anyone run the 5W-20 when they can use the 0W-20? I've had excellent used oil analysis running M1 0W-20 16,000 km.
  11. jayman

    jayman Senior Member

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    You must have read that thread I had about the weird used oil findings when my Prius was about a year old. The samples had sodium, sulfur, dirt, etc etc

    Once Toyota Canada found out I was using Mobil 1, they automatically blamed the synthetic. Even though a virgin sample from the same lot excluded Mobil 1 as a possible source

    I finally managed to snag a sample of the dealership oil from their bulk lube system. Talk about crap. It was even contaminated, the testing lab pointed that out. I took a photo of the tote bin they had outside for the bulk lube system

    The tote bin breather was simply an inverted pipe. Standard engineering practice is to use a desiccant breather vent. Once I sent that to Toyota Canada, they very quickly closed the file and never said another peep about it.

    Gee, wonder why???

    :confused:
  12. dpguest

    dpguest New Member

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    I have read this thread in its entirety and am not sure I understand it all or can draw a conclusion.

    I would like to use synthetic oil in my first oil change... I intend to use a Toyota filter and Mobil 1. I am going to change the oil every 5000 miles... not personally, but have a local garage do it and give me a receipt.

    I just am not sure which Mobil one I should use.


    Is there a conclusion or does it not matter?

    thanks great Priusgurus....:)
  13. strider5

    strider5 New Member

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    I bought the 5qt bottle of Mobil 1 0w30 today from Walmart for $21.87.
  14. bigbearballs

    bigbearballs Junior Member

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    I live in TX and summer is approaching, what's the best oil for me? What interval have you fellows been using? I think 5000 miles is too soon.
  15. jayman

    jayman Senior Member

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    Prius cars operated in other markets - say the EU or Japan - running the same exact motor will specify a wide range of viscosity. You should be fine with 5W-30 year round. If very cold, certainly below -20 F, I would then run the 0W-30. You can also run the 0W-30 year round



    I hope this "local garage" is aware of some unique properties of the Prius. Most important would be the operation of the Prius, if this is the first hybrid car they have ever serviced

    A lot of us have had issues with novices and unskilled people - or those who simply didn't give a s*** - trying to operate our Prius. In some cases, there has been damage.

    Say the person who washes the car, or details it, and wants to listen to the radio. Instead of pushing on the brake pedal and then pushing Start, they simply push the dash button. Dash lights up, radio works, etc. And the battery is discharged

    Or the person who drives into the garage and notices the motor has "automatically" turned off. So they put it up on the lift, drain the oil, and in the meantime the traction battery charge has dipped to the point where the motor automatically starts again. With no oil in the sump.

    Or, the "local garage" using the wrong oil filter, which allows all the oil to leak out and seize the motor. Toyota naturally denies a warranty claim, and the garage claims it isn't their fault. Oil overfill is another common complaint, get 4 quarts of oil, drain half a quart into another container, and hand them 3.5 quarts of oil. That is PLENTY

    So make sure to carefully explain the operation of the Prius to this "local garage"
  16. jayman

    jayman Senior Member

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    Well, the Prius operated in Spain has a suggested viscosity range from 5W-30 up to 20W-50. See attached. Here in North America, 5W-30 or 10W-30. You should be fine with either

    I agree with synthetic, especially one rated ACEA A3,B3/B4, 5,000 miles is much too often. The same car operated in the EU is 12 months or 10,000 miles. However, for "warranty" Toyota does require a 6 month or 5,000 mile interval

    I greatly exceed that, but I also do used oil analysis. It would be *very* difficult for Toyota to "prove" my oil interval was the cause of any motor issue. My Prius is off warranty anyway

    Attached Files:

  17. strider5

    strider5 New Member

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    anyone know where I can get Used Oil Analysis done in the US? Whats a ballpark cost to have it done?

    Jayman: is there any issue mixing Mobil 1 0w30 and 0w40? I have a couple quarts of 0w40 left from my old car, so if I can use it without issue that would be nice.
  18. drees

    drees Senior Member

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    Blackstone Labs, costs about $20.


    Nope, mix away. If you're worried about it only mix 1 qt of the 0w40 with the rest being 0w30, but the 0w40 is a good oil (I'm assuming Mobil 1).
  19. jayman

    jayman Senior Member

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    Go ahead and use it up. I'm currently using Mobil 1 0W-40 in my FJ with great results. Using 2 qts of 0W-40 and 1-1.5 quarts of 0W-30 won't affect the Prius
  20. Rest

    Rest Active Member

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    I never said 0W was "bad" compared to 5W. All I said was that in the States, it is not approved for 2004-2008 Prius models. I would much rather run the 0W for the fuel savings but, since it is the U.S. division of Toyota that warranties my Prius, I have no choice but to use the weight of oil they suggest if I want to keep my engine warranty. Once the warranty is up I am switching.
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