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Switching to a thicker oil?

Discussion in 'Gen 2 Prius Main Forum' started by Dummy, Aug 1, 2023.

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  1. Dummy

    Dummy Member

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    I’m at about 240k and I always run 5w30. If I use full synthetic it burns a quart every 3500 miles. It uses a quart every 3000 mile if I use conventional. I’ve thought about switching to a heavier oil to help seal up the now worn clearances in the engine. Good idea? Bad idea? I’m currently getting 43 mph on the computer, will it effect that?
     
  2. pasadena_commut

    pasadena_commut Senior Member

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    1 qt. every 3500 miles with synthetic? Lots of new from the factory cars burn that much these days. I would just keep doing what you are doing for now, but do keep an eye on the dipstick in case it changes.
     
  3. Tombukt2

    Tombukt2 Senior Member

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    I use more than that and it's not leaking pretty common for the 1NZ engine of course I'm also over 300,000 and this is exactly about what I expected as far as oil consumption is going no problem I run cheap oil and that's all that's required now other than that it runs fine quiet good acceleration I was getting 47 mi to the gallon up until a few weeks ago I got to take a look and see what's keeping me down at 4142 now.
     
  4. Dummy

    Dummy Member

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    I’ve never heard of a car that burns oil when it’s new
     
  5. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    yeah I do not know about that on a new car either.. but for a well worn car? Sure, why not?

    Now the thing is, a thicker oil is likely to cost you a little in terms of MPG. Might be worth burning that quart of oil in the end.
     
  6. Dummy

    Dummy Member

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    Your name doesn’t exactly scream Prius owner does it
     
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  7. MCCOHENS

    MCCOHENS Member

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    The new 0W oil has a reputation of burning oil in new engines. Some cars burned thru the whole crankcase before an oil change, causing an interesting warranty claim. Not heresay or rumor this is from a dealer tech.
    I was an advocate of thicker oil when an engine got past 150K miles but no more. Clearances and oil pumps are not designed for this. I have changed my policy but no change in consumption or MPG.
     
  8. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Glass houses, dude.
     
  9. Dummy

    Dummy Member

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    So what is your opinion? It’s unclear whether you are for or against running a thicker oil.
     
  10. Mendel Leisk

    Mendel Leisk Senior Member

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    Try it, say 10W40, see how it goes.
     
  11. sam spade 2

    sam spade 2 Senior Member

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    Yes, do it. It can't hurt anything.
    Get a "high mileage" synthetic oil, which is thicker and has additives for the seals.
    Whether or not it helps depends on exactly why it is using the oil in the first place.
     
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  12. Mendel Leisk

    Mendel Leisk Senior Member

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    If you go to a high mileage oil, I've read you want to stick with from then on: it has additives that swell seals, and going back to regular oil the seals will shrink, leak more than at the outset.
     
  13. pasadena_commut

    pasadena_commut Senior Member

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    Widely reported issue:

    Some Newer Cars Can Burn Lots of Oil - Consumer Reports
     
  14. wjtracy

    wjtracy Senior Member

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    Per Sam above, Mobil-1 used to have high mileage versions...not sure current product line up.
     
  15. MCCOHENS

    MCCOHENS Member

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    I am using 5W in all my cars now. The 10W is becoming harder to get and I have found no difference in oil consumption. Just finished break in on a new suby motor, try finding non synthetic 20W oil. Darn near impossible.
     
  16. edthefox5

    edthefox5 Senior Member

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    I ran 40 weight oil for years when my G2 started some very minor oil loss at 100,000 miles. It stopped that and really did not eat any oil when I sold it 15 years later at 165,000 miles.

    But I run really expensive oil.

    And Dummy at 43 mpg's your in Stage 1 of Hybrid battery failure. That means the engine has to make up the power loss of the hybrid battery so is working much harder. The battery power loss happens so slowly over the years you don't even notice that lack of power so your pushing the gas pedal harder to make up for it. That's why your getting 43 mpgs.