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  1. Flying White Dutchman

    Flying White Dutchman Senior Member

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    wy not use 5w40 oil in the prius?
     
  2. N3FOL

    N3FOL Member

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    Not recommended by Toyota.
     
  3. donee

    donee New Member

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    Hi lIon,

    Because the clearances in the engine are designed for 5W30. And the 40 wieght oil may be to viscous to fully penetrate into the small gaps between the parts at colder temperatures.
     
  4. jdenenberg

    jdenenberg EE Professor

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    The thicker oil will also reduce MPG.

    JeffD
     
  5. jayman

    jayman Senior Member

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    The Prius operated in the EU "suggests" a 5W-30, but most ACEA rated motor oils are xW-40, such as 5W-40 or 0W-40

    I have tried many different oils in my Prius, ranging from the dealer 5W-30, Mobil 1 5W-30, Esso XD-3 15W-40 (In summer), Mobil 1 0W-30, and Mobil 1 0W-20

    Running the 15W-40 in summer, the same stretch of Trans Canada that gave me around 4.8 l/100 km at 110 km/h returned 4.9 l/100km at 110 km/h. That is comparing 57.6 mpg to 58.9 mpg. No unusual noises, motor quiet as usual

    I used the 15W-40 as I had just changed the oil in the Ford work truck and the diesel tractor at my hobby farm, and had 3 litres left over. I didn't want to keep an opened jug another year, and the Prius was ready for an oil change, so I thought "why not?" The used oil analysis came back fiine too

    Comparing Mobil 1 5W-30, 0W-30, and 0W-20, I have not noticed any difference in city or highway fuel economy running Spring-Summer-Fall. The Mobil 1 0W-20 helped the fuel economy a bit in bitter cold temps, especially -30 C and colder.

    I'm currently running the 0W-20 year round in the Prius to not have to monkey with different grades. My used oil analysis is fine at 16,000 km, and I figure the 0W-20 faster cold start flow is beneficial

    The 5W-40 oils are designed to meet the very tough ACEA A3, B3/B4 specs, which cover very severe operating conditions and highly extended oil change intervals. Most synthetic 5W-40 oils should not be used in temps of -30 C or colder

    If you want a tough oil with good cold temp and cold start flow, why not consider Mobil 1 0W-40? It meets the tough ACEA A3, B3/B4 specs. I'm currently using this oil in my FJ Cruiser, as I have had shear issues with the recommended 5W-30 oils

    Mobil 1 0W-40

    The MRV at -40 is 26,242 cP, which is well under the maximum yield stress of 60,000 cP
     
  6. jayman

    jayman Senior Member

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    Are you located in the EU? In that case, a 5W-40 is a very common viscosity.
     
  7. Flying White Dutchman

    Flying White Dutchman Senior Member

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    yes EU...

    i only ues 5w40

    its the best oil here!! buth maybe not good for the prius?
     
  8. jayman

    jayman Senior Member

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    I wouldn't be surprised if the Toyota dealer isn't filling with an ACEA spec 5W-40 or 0W-40. Especially if you live in Germany and routinely travel the Autobahn

    I visited the BP web site for the United Kingdom and selected their lubricant advisor. For the Prius their primary recommendation is to use the synthetic Visco 7000 0W-40.

    As an alternative, they recommend Visco 5000 5W-30 "Fuel Economy" formulation. If the temps are warmer than -7 C, you can use the Visco 20W-50. But the primary recommendation is the synthetic 0W-40

    I have no doubt the synthetic 5W-40 is the best in Europe. The ACEA testing process - especially to rate A3, B3/B4 - is far beyond what the API does here in North America to rate an SL or SM oil

    I'm also going to guess that the oil service interval for your Prius is 12 months or 16,000 km, but please correct me if I'm mistaken.

    I would appreciate it if you could consult your EU market Prius owner handbook and maintenance supplement and let me know what Toyota recommends for an oil service interval if operated in the EU, and what the viscosity recommendations are

    I ask this as I used to have a 1990 Toyota 4Runner with a 3 litre V6. I managed to get a UK handbook while over on business, and it suggested regular viscosity of 10W-40, 15W-40, or 20W-50. A 5W-30 was unsuitable in temps warmer than +10 C.

    So I always ran either Mobil Delvac 5W-40 or Esso XD-3 15W-40 in summer. At 320,000 km the dealer here did a free head gasket service, as there had been some issues with head gasket failure in that motor

    He was shocked at the condition of the motor. The crosshatch was still on the cylinders. If he had to guess, he would have thought the motor had 15,000-20,000 km on it, not +300,000 km on it

    I'm sure you will be just fine with a synthetic 5W-40. If you live in an area that has winter conditions colder than -30 C, I would recommend a 0W-40.
     
  9. Flying White Dutchman

    Flying White Dutchman Senior Member

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    i now got synt. 5W30 from shell with a cleaning formula in it! Shell Helix Ultra AG 5w30
     
  10. bwilson4web

    bwilson4web BMW i3 and Model 3

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    "Shear issues?" Could you expand on this?

    Bob Wilson
     
  11. ken1784

    ken1784 SuperMID designer

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    Japanese hypermilers are using 0W-20.

    Ken@Japan
     
  12. jayman

    jayman Senior Member

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    I went to the Shell EU site at

    Shell in the UK - Shell Helix Ultra

    That particular Helix appears to be a good oil, is primarily recommended for longlife servicing in Opel and Vauxhall autos

    I used the Shell lubricant advisor

    Shell in the UK - Shell Lubricants UK Lubematch Tool

    And selected Germany, English (As I can barely order a meal in German), Cars, and Prius. Shell's primary recommendation is their Helix Ultra Extra 5W-30, but you can also use 15W-40 or 20W-50 depending on ambient temperature

    The BP site has their Visco 7000 0W-40 as the primary recommendation for the EU

    I'm wondering what viscosity oil the EU Toyota dealers use? I didn't have a chance to ask this time out, last time in the UK the Toyota dealer claimed to use a synthetic 10W-40 in all models, with the exception of certain turbodiesels which required a synthetic 0W-40
     
  13. jayman

    jayman Senior Member

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    Certainly

    My FJ Cruiser the dealer wanted the first oil change at 3,000 km. I found that a bit odd as for my Prius he wanted the first oil change at the usual North American interval of 8,000 km

    So at 2,400 km I did a sample, and the testing lab called me at work. Although Si and Cu were high but "normal" for breakin (Si was 187, Cu was 48), the TBN was 1.0. Essentially, the oil was already used up

    The viscosity at +100C was only 6 cSt, that indicated shear assuming an xW-20, and very bad shear assuming an xW-30. The nitration UFM # was 29. They suggested an immediate oil change

    Dealer changed the oil for free and used conventional Valvoline 5W-30, the mechanic was pointing out some of the 4wd features while he was servicing the FJ so I saw him using the bottles

    I sampled that oil after 2,800 km and it had issues too. TBN was 4, which is normal for conventional min-spec API oil. Viscosity at +100 C was 7 cSt. Nitration UFM # was 20

    So I changed the oil and filter myself and used Esso XD-3 0W-40. This is a heavy duty oil rated for severe turbodiesel service and arctic conditions. After 5,000 km the viscosity at +100 C was 13 cSt. The fresh viscosity is around 14.8 cSt. TBN was still 10. Nitration UFM # was 12. Si was 25

    A local shop had Mobil 1 5W-20 on sale, so I thought I would try it. After 2,500 km, viscosity at +100 C was only 5 cSt. TBN was fine at 8. Other values were ok too. So I changed it and put in Mobil 1 0W-40, which is their "European car formula." We'll see how it holds up when I sample in March or April
     
  14. jayman

    jayman Senior Member

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    Ken

    I run Mobil 1 0W-20 year round now, as I have excellent lab results from this oil

    I have only noticed a fuel economy improvement in city driving running this oil in very cold temps of -20 C and colder. I primarily use this oil as it has proven cold temp performance at -40

    In temps of +25 C to +39 C, running 15W-40, 5W-30, 0W-30, and 0W-20, I have noticed no real difference in fuel economy city or highway. For example, the 15W-40 in summer on the highway might return 4.8 l/100km. The 0W-20 will return 4.7 l/100km

    I think for bitter cold temps a 0W-xx oil should be a no-braiiner. It's important to realize that some conventional API oils have "unusual" cold temp properties. They rely on heavy doses of Pour Point Depressant. A clue to that should be the ASTM Pour Point being HIGHER than the MRV BPT rating

    As an example, a conventional 5W-30 might have a ASTM rated Pour Point of -32 C. Remember there is no legal requirement for Pour Point in the SAE J300, this is only a test point. The MRV BPT might be -38 C. How can an oil "flow" at -38 C when it won't "pour" colder than -32 C?

    Because of all those polymers in the oil, the Pour Point Depressant

    Once an oil is aged, it will no longer behave like that. Acid buildup, nitration, etc, will render the Pour Point Depressants useless. This is reflected in the Gellation Index values, and why conventional min-spec API oils have a rating of 12 or higher. This is a "warning" value

    A good synthetic oil has no Pour Point Depressant. What you see is what you get

    Let's also keep in mind that a 0W-20 may be impossible to find in the EU or in Australia. Up until very recently, Toyota Australia still used 20W-50 or 15W-40. No matter if VVT-i or not
     
  15. ken1784

    ken1784 SuperMID designer

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    Thank you for your comments.
    Japanese Prius owner's manual says the recommended oil grades are 0W-20, 5W-30, 5W-20 and 10W-30.
    Toyota Japan supplies their genuine Castle brand 0W-20 oil.

    Ken@Japan

    PS: There are a lot of 0W-20 suppliers including Shell and BP in Japan. Nissan, Mazda and Honda also supply their 0W-20 oil.
     
  16. jayman

    jayman Senior Member

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    I haven't seen it in EU, at least not the last time I looked around a week ago. Although the newer EU cars are specifying a synthetic 0W-30 or 5W-30, the majority still specify a synthetic 5W-40 or 0W-40. Last time in Australia around 2 years ago, the Toyota dealers were still using 20W-50 or 15W-40

    Interesting about the owner manual. Ours will state 5W-30 only, although they make an exception that 10W-30 may be used.

    I'm using Mobil 1 0W-20 year round in my Prius. I'll probably use Esso XD-3 0W-40 or Mobil 1 0W-40 year round in my FJ Cruiser

    I found a manual section for an EU Mazda. Interesting what they have to suggest about running viscosity
     

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  17. ken1784

    ken1784 SuperMID designer

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    Just FYI...
    Following is our manual.

    Ken@Japan
     

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  18. jayman

    jayman Senior Member

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    Ken

    THANK YOU! That is EXACTLY what I have been asking for, only for the past 2 years. I'm not much of a touchy-feely person, but you deserve a rib-crushing bearhug

    Of course, the North American manual states 5W-30 only, with 10W-30 possible. I would very much appreciate it if our EU members would be so kind as to photocopy or scan the appropriate manual section and post here on PriusChat

    jay
     
  19. sub3marathonman

    sub3marathonman Active Member

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    However, it is interesting that in Japan there is no oil recommended that has a higher upper viscosity rating of greater than 30.
     
  20. jayman

    jayman Senior Member

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    A lot of that probably has to do with driving cycle. In city short trip, I'm a big fan of running the lightest viscosity I can find. Even in summer, a 0W-20 will provide lubrication benefits to any motor

    In the EU, where I guess they expect a lot of high speed autoroute driving, they still seem to prefer an xW-40. For example, if you go to BP's lubricant selector site in the UK, enter the vehicle, it suggests using their synthetic Visco 7000 0W-40