Another oil burning Prius :(

Discussion in 'Prius v Main Forum' started by Aaron Vitolins, Jun 9, 2017.

  1. emendia

    emendia Junior Member

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    So here's the thing... I have a 2007 Prius with 207,000 miles. It's going through around two to three quarts every 2,500 miles or about a quart every 1,000 miles.

    It was worse, but PCV valve was recently changed and that's helped. Plugs are fairly new as are fuel injectors.

    Trouble is I am getting a persistent PO420 catalytic converter mal-efficiency code. I recently read that could have been caused by the excessive oil burning; hence the change of the PCV valve.

    I'm in California, so an aftermarket cat is out if the question making replacing the cat a 2500 to 3000 dollar fix. But even if I have the cat changed, with the engine still dumping oil, I'd run the risk of the new cat going kaput too in short order.

    So what do I do? Junk the car? Replace the engine, then the cat (probably cost upwards of 6k to do both!? Sell the house and move to Arizona?
     
    #101 emendia, Dec 27, 2019
    Last edited: Dec 27, 2019
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  2. bisco

    bisco cookie crumbler

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    3 is a good option :p 2 is realistic, 1 sounds like good money after bad

    they are stealing 2007 cats in la, might be worth a few dinero
     
  3. tvpierce

    tvpierce Senior Member

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    Incorrect. The oil burning Prius engines are not burning oil because they're worn out. They're burning oil because the rings are sticking. If the rings and pistons are replaced, the oil consumption problem is corrected.
     
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  4. tvpierce

    tvpierce Senior Member

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    That could very well be a faulty/lazy Oxygen sensor. Here's why:

    The system measures the efficiency of the catalytic converter by comparing the readings of the two oxygen sensors -- one upstrean of the converter, and one down stream of the converter. There's a range of acceptable difference between the two readings that tells the system that the converter is operating properly. If the reading is out of range, it throws the code.

    But there are two scenarios that will give a reading outside the acceptable range:
    1) the catalytic converter is not operating properly.
    2) one or both of the oxygen sensors are giving faulty readings.

    Given your situation, I'd start by replacing one or both of the oxygen sensors.
     
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  5. mikefocke

    mikefocke Prius v Three 2012, Avalon 2011

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    I'd read the voltages of the sensors. There are two of them probably and the one nearest the engine measures what comes into the cat and the one after the cat checks to see if the cat is working. If the cat has been compromised by a incomplete combustion cycle residue in the exhaust, then the cat is not gonna be able to clean up the exhaust after a while.
     
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  6. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

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    Or a soak with some solvent?
     
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  7. John Valkenburg

    John Valkenburg Junior Member

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    I had a Prius II that was burning a lot of oil. The fix was to add 1/2 can Rislone concentrate and 1/2 can Seafoam to a warm engine and drive for about 20 minutes. Changed the oil after a week, and repeated the same thing. It loosened the oil rings and stopped the burn completely. Once a summer, I repeated this just before the summer oil change and drove the car to 400K. Best of luck.
     
  8. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

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    Not sure I'm understanding: you did a second round, ie: added the Rislone/Seafoam a second time, drove another week, did a second change?

    I'm thinking it's just once per year, but not sure.
     
  9. MVPLRJohnson

    MVPLRJohnson Junior Member

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    Which Rislone was used?

    Thank you,
    MJ
     
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