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5w-30 syn MPG vs 0w-20 syn MPG

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by The Critic, Jun 6, 2013.

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  1. The Critic

    The Critic Resident Critic

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    It has been about 5,000 miles since my last oil service and it occurred to me that I should try 5w-30 synthetic (instead of 0w-20) to see if there are any trackable differences in fuel economy. If I were to do this, I would run Mobil 1 5w-30 for 5,000 miles and use "Trip B" to compare.

    Per the owner's manual, Toyota does allow for the use of higher-viscosity oils if the vehicle is operated under high-speed/high-stress conditions, so I would not be doing anything terribly outrageous. Plus I am out of warranty already, so I am on my own.

    Has anyone used 5w-30 synthetic oil in their Gen III, as opposed to the recommended 0w-20?
     
    #1 The Critic, Jun 6, 2013
    anonymous and mmmodem like this.
  2. mmmodem

    mmmodem Senior Taste Tester

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    Sounds like an interesting experiment. If my car ever starts to consume oil that requires me to top up between OCI then I'll be switching to a heavier weight oil. It'll be nice to know what kind of fuel economy hit I would take.
     
    #2 mmmodem, Jun 6, 2013
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  3. Former Member 68813

    Former Member 68813 Senior Member

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    I'm not sure anyone have done 0W20 -> 5W30. IIRC, plenty of people did 5W30->0W20 in 2nd gen. That should give some ideas. The MPG difference will differ with ambient temps and driving style (city/hwy, trip length, etc).
     
    #3 Former Member 68813, Jun 6, 2013
  4. tankyuong

    tankyuong Senior Member

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    I had 5w30 Dino oil and didn't see a difference in mpg
     
    #4 tankyuong, Jun 6, 2013
  5. Bill Norton

    Bill Norton Senior Member

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    How would you factor out ambient temp changes?
    FE tracks temp.
    If you could knock out two oil changes ( 10k ) during the hot summer months you might have some good data.
     
    #5 Bill Norton, Jun 6, 2013
  6. The Critic

    The Critic Resident Critic

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    Here in Monterey, it's a fairly constant 50-65 year 'round.
     
    #6 The Critic, Jun 6, 2013
  7. Former Member 68813

    Former Member 68813 Senior Member

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    I think difference should be like 1%. Can't reliably measure that outside a lab. Short tripping in very cold weather could show bigger difference though.
     
    #7 Former Member 68813, Jun 6, 2013
  8. Bill Norton

    Bill Norton Senior Member

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    "Here in Monterey, it's a fairly constant 50-65 year 'round."



    Dang,,, Never mind.

    I hope you know how lucky you are !!!
     
    #8 Bill Norton, Jun 6, 2013
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  9. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Isn't 5W30 or something similar spec'd in Australia?
     
    #9 Mendel Leisk, Jun 6, 2013
  10. Former Member 68813

    Former Member 68813 Senior Member

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    0w20 through 20W50 is good to go down under.
     
    #10 Former Member 68813, Jun 6, 2013
  11. xs650

    xs650 Senior Member

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    I think the Toyota spec gives a nod to local custom where government regulations don't discourage it. Traditionally, some Australians would have used bitomen in their engines if the could have gotten it to pour out of a can.
     
    #11 xs650, Jun 6, 2013
  12. AwesomeAccessory

    AwesomeAccessory New Member

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    I just put 0w20 in my 08, usually use 5w30

    car seems to be revving really high, or maybe I am just oversensitive and looking for trouble with my oil change

    happened immediately after oil change, should I empty it and refill it with 5w30---- or is this all in my head?
     
    #12 AwesomeAccessory, Jul 22, 2013
  13. wjtracy

    wjtracy Senior Member

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    ...well winter would have been a better time for the 0w-20 experiment in a Gen2. But I believe Toyota USA has said it is OK so you shoud be OK. You want to drain after 5k miles, according to Toyota USA.
     
    #13 wjtracy, Jul 22, 2013
  14. AwesomeAccessory

    AwesomeAccessory New Member

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    yeah I grabbed it for my Altima, and just grabbed two to make life easier (oh well!)

    could this be why its revving high? almost like it's not shifting into first gear, a real struggle.

    maybe ill just put the radio louder -- that oughta fix it
     
    #14 AwesomeAccessory, Jul 22, 2013
  15. The Critic

    The Critic Resident Critic

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    Just wanted to follow up on this matter -

    I did an oil change last night using 5W-30 synthetic instead of using 0W-20 synthetic.

    For the record, I used Quaker State Ultimate Durability 5W-30 synthetic.

    From a mpg standpoint, it is too early to tell, but I still got 49.5 on my trip to Sacramento this afternoon. Repeated short trip driving may yield different results though, so we'll see.

    Other than that, I did notice that the engine is noticeably quieter at idle. Perhaps that being at 110k miles makes the engine benefit more from thicker oil?

    I plan to run this fill for 5,000 miles, replace with the same, and then send in a sample after another 5,000 miles (at the 120k mark).
     
    #15 The Critic, Jun 13, 2015
    anonymous, CR94 and Mendel Leisk like this.
  16. bisco

    bisco cookie crumbler

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    it took you two years to pull the trigger?:p
     
    #16 bisco, Jun 13, 2015
  17. The Critic

    The Critic Resident Critic

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    Yup.


    iPhone ?
     
    #17 The Critic, Jun 13, 2015
  18. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Thanks for posting. Look forward to the results. :)
     
    #18 Mendel Leisk, Jun 14, 2015
  19. jjPrius

    jjPrius Junior Member

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    Were you having a consumption issue as well?
     
    #19 jjPrius, Jun 14, 2015
  20. The Critic

    The Critic Resident Critic

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    No significant consumption - and judging from what I've seen, I am quite lucky about that.

    I have gone down to 5k oil changes and the oil level never dropped more than 1/4 qt between changes.


    iPhone ?
     
    #20 The Critic, Jun 14, 2015
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