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Do not use premium fuel on prius!!!

Discussion in 'Gen 3 Prius Technical Discussion' started by Ernesto Chavez, Jun 30, 2016.

  1. Tideland Prius

    Tideland Prius Moderator of the North
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    The manual for the Gen 3 states 0W-20 or 5W-20 (except for 2011-2015 where 0W-20 is recommended). At least in Canada, 0W-20 has been recommended for 2011 (give or take a year) models and newer.

    Why do you even need 0W in NM? 5W-xx should be fine. (like 5W-20). Also, isn't 40 thicker than 20? You've contradicted yourself (but you have good advice about not getting stranded because of thicker oil)

    Do tell. My dealer regularly recommends a fuel injection cleaner service even though it's not part of the official Toyota maintenance schedule.
     
  2. Redpoint5

    Redpoint5 Senior Member

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    Premium causes my exhaust to smell on my bike, and the manual specifies regular 87 octane for the Honda CBR600 F4i. I get no performance improvement from running higher octane, even on the track.

    Premium doesn't have more detergent, either, so the advice to run fuel system cleaner if you run regular is bogus. Top Tier certified fuels will have higher levels of detergent.

    I've never found a fuel injected car to perform better on premium when it was designed to run on regular. With that said, I can tell a very slight difference in performance running premium in my Acura, which specifies 91 octane.
     
  3. wjtracy

    wjtracy Senior Member

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  4. StarCaller

    StarCaller Senior Member

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    meaning more wear with thinner oil/

    yep, 40 IS thicker/
    going into albuquerque in the summer means pretty often get stuck in traffic with temperatures higher than a 100 degrees/
    now living in the mountains, temperatures in the winter are often as low as 10s or 20s/

    that's why I use 0w-40 year round//
     
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  5. bhtooefr

    bhtooefr Senior Member

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    Not necessarily.

    Thinner oil can get into narrower passages more easily, meaning that sometimes wear, especially startup wear (which is more of an issue on a hybrid, with frequent engine shutdowns), can actually be reduced.
     
  6. StarCaller

    StarCaller Senior Member

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  7. bhtooefr

    bhtooefr Senior Member

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    The 20 is what matters on a hot start, though, not the 0W.
     
  8. Coast Cruiser

    Coast Cruiser Senior Member

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    Amen to that!
     
  9. Mendel Leisk

    Mendel Leisk Senior Member

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    I have a hunch that 0W40 would be a little thicker when cold, comparing to 0W20.
     
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  10. bhtooefr

    bhtooefr Senior Member

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    It'll depend on the specific oil. (IIRC, Toyota Genuine Motor Oil 0W20 is light even for a 0W20.)
     
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  11. MrMischief

    MrMischief Active Member

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    Funny enough, there's a video for that. I am curious why one needs gloves and the other doesn't, but it's dumb silliness if nothing else.

     
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  12. qdllc

    qdllc Senior Member

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    Well, this runs back to when fuel injection was a new concept. Lots of people complained of lost performance, and running a bottle of fuel system treatment easily restore performance.

    Now, certainly, fuel delivery systems are higher quality and fuels tend to have more detergent additives, but depending on the motor, carbon deposits form and negatively affect plugs and valves. Unless you always use fuel with a system cleaner in it (e.g., Techron), this problem will crop up from time to time.

    Personally, I use B-12 Chemtool. It’s the same stuff as Seafoam but half the cost. It’s a fuel system safe industrial solvent. I put a bottle in the Prius once every 10,000 miles. I use 1/3 to 1/2 of a bottle in the motorcycle depending on use. If it sits over the winter or if I put several hundred miles on while always buying regular gas. Never had a fuel system or performance issue.
     
  13. alanclarkeau

    alanclarkeau Senior Member

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    Which part of the world are you from? What is relevant in EU is irrelevant in Singapore.
     
  14. qdllc

    qdllc Senior Member

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    United States.
     
  15. prius_deep

    prius_deep Member

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    gen 2:
    Toyota Hybrid System Diagnosis - Course 072; Section 3; 3-4:

    Do not use premium gasoline. It may cause starting problems with the
    Prius. There is no gas mileage benefit when using premium gas!

    Starting may occur many times in a single drive cycle unlike
    conventional vehicles compounding potential "hot soak" issues.
     
  16. padroo

    padroo Senior Member

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    I have looked at different owners manuals on the Internet from different countries and it seems they use different octane fuels. More research needs to be done.
     
  17. alanclarkeau

    alanclarkeau Senior Member

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    Which part of the world are you in? (your profile is ambiguous) - there are members from dozens of countries - your comment is likely not of interest/relevance to 99% of them depending on where your "road" is. This is a Gen 3 Thread, I see you drive a Gen 4, but you mention "gen 2".

    TOYOTA specifies PREMIUM MUST be used for Gen 3 here.
     
  18. fuzzy1

    fuzzy1 Senior Member

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    Don't forget that there are several different octane rating scales. E.g. the EU scale is different than the US scale.
     
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  19. wjtracy

    wjtracy Senior Member

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    The Bentley Publishers Toyota Prius 2004-2008 Repair and Maintenance Guide also makes the comment about not using Premium gasoline(due to hard starting), but I have never figured out where they got that comment. Nobody here ever reported a starting problem.

    MPG is going to be based on energy content (not octane rating), which energy content is not automatically better for Premium, and is definitely not better for Premium in RFG areas. But some stations in some locations Premium could be better for MPG (eg; Canada where Premium is often E0). .
     
    #59 wjtracy, Apr 29, 2018
    Last edited: Apr 29, 2018
  20. StarCaller

    StarCaller Senior Member

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    neone got a comparison between australian & us-american fuel octane ratings?
    what's premium in australia might be regular here/