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2006 w 128k miles: Change to Synthetic Oil? NOT Losing Oil Now

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Priusjames, Jun 11, 2021.

  1. Priusjames

    Priusjames Member

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    The car does fine, but I'm noticing the vat dyno oil I've always used gets dirty really fast and would like to see cleaner oil when I check the stick. I was just grossed out by my dipstick and there are only 1k miles on the oil. Ugh.

    2 Q's:
    1) Is clean/clear ever going to happen if I change to synthetic, or will the old crud in the engine turn the new stuff dark and gross forever? Maybe it'll get clearer/purer after a couple of changes?
    2) Does the conventional wisdom "Do not change what is not currently a problem" apply, or is it better to change to synthetic before problems (burning, etc.) start to exist in a Gen 2?

    Most of the threads I've read about this are addressing cars that are already burning oil.
     
  2. PriusCamper

    PriusCamper Senior Member

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    Synthetic oil being cleaner than regular oil after only 1K miles is perhaps the most notable difference I've experienced. Also being able to go 8K miles or more is a big help due to me going on a 1500-2000 mile road trip every other month. And maybe 0W-20 has a very slight MPG improvement...
     
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  3. Mendel Leisk

    Mendel Leisk Senior Member

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    Any oil turns black, fast; that’s a detergent oil doing it’s job. I’ve taken pics, a spaghetti sauce jar with Toyota 0W20 (synth) drained after maybe 2-3k kms, and it’s black as ink. Don’t kid yourself that synth is some panacea.
     
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  4. JC91006

    JC91006 Senior Member

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    What? Pandemic driving for 6 months?
     
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  5. Raytheeagle

    Raytheeagle Senior Member

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    That could even be normal miles for him:p.

    But COVID didn't help the garage queen stretch her legs very often:cool:.

    Maybe soon(y).
     
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  6. Priusjames

    Priusjames Member

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    The answer to question number 1, thanks!
     
  7. privilege

    privilege Active Member

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    put a bore scope down into the valve cover and look.
    put the same bore scope up through the drain hole and look.

    if you have a ton of sludge it will take a while to filter and clean it out just by doing oil changes. there are products that will make the sludge become dilute in the oil again, but you'll have to follow their instructions to get all the sludge out of the engine.

    after that, yes, you will have clear/honey looking oil for a few thousand miles with full synthetic, if you don't have a bunch of blow by/bad rings.

    you can also use atf/acetone to try and unstick rings, that will raise compression/efficiency and make the oil stay clean longer.

    1 depends on how much gunk you have
    2 there are a million opinions on this. mine is: user whatever oil brand you like and change it every 3-5k miles.
     
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