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25K Mile UOA Results

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Dark_matter_doesn't, Jun 27, 2011.

  1. Dark_matter_doesn't

    Dark_matter_doesn't Prius Tinkerer

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    Results from my mid-10K oil check @ 25K miles, including all the prior UOA results below. All on Mobil1 0W-20 since the first change, regular Toyota oil filters up to 10K miles, then TRD oil filters since.

    [​IMG]
     
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  2. stream

    stream Senior Member

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    For the uninitiated, could you provide some commentary on the results?
     
  3. twittel

    twittel Senior Member

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    I had to zoom the text to 400% to read, but iron deposits are within normal limits. Blackstone says that all is good and they hope to see this customer at next oil change.
     
  4. pjksr02

    pjksr02 Active Member

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    Very consistent results, and good results.

    Looks like your last interval was with the newer Mobil-1, where Ca and P are lower.

    It'd be interesting to see results with 0W-30, for curiosity's sake. Hope somebody runs a sample someday...
     
  5. Dark_matter_doesn't

    Dark_matter_doesn't Prius Tinkerer

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    Iron and aluminum are primary engine materials, along with chromium that hardens steel. Low levels mean low wear in the engine.

    Tin and copper are used in engine bearings, so low levels of these metals mean bearings are in hood shape.

    In other threads, concern had been expressed about relatively high silicon levels in new engines (possibly from casting sand residues). That's one reason I changed my oil early the first time. Note that Si levels went down 4x by the second oil change, and had gone down by nearly 10x at 10k miles. Si is not good in an engine.

    One important parameter is TBN, which measures the amount of additives in the oil. Mobil 1 0W-20 has a TBN of 9.8 out of the bottle, and a level of 1.0 or less means the oil is worn out. Mobil 1 will go more than 10k miles in a Prius.

    I'll do the UOA @ 30k miles, then at 10k intervals.
     
  6. cwerdna

    cwerdna Senior Member

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