Does the 1NZ-FXE engine have piston ring problems like the 2NZ?

Discussion in 'Gen 2 Prius Technical Discussion' started by Pd30242, May 2, 2025.

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  1. Pd30242

    Pd30242 Junior Member

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    I recently got a JDM 1NZ-FXE and I was wondering if I should swap out the rings while its not in the car. I opted to replace my current 1NZ because of oil burning and I got a tremendous deal on a JDM engine. So my questions is are the 1NZ's piston rings faulty like the 2NZ's?
     
    #1 Pd30242, May 2, 2025
    Last edited: May 3, 2025
  2. PriusCamper

    PriusCamper Senior Member

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    Never read on here about Prius C engines having the same bad rings as Gen3...

    Also I don't know much about 1NZ's ring problem. Where can I go to learn more? Or at least can you elaborate?
     
    #2 PriusCamper, May 3, 2025
  3. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    There is a history of oil burning in older (say, pre-2012) 1.5L engines, but it's not the same.

    The 1.8L 2ZR engine was given special low-tension piston rings in an effort to increase fuel efficiency through reduced pumping loss. That's "the big oil burning problem" with that engine. I understand they gave up and started shipping normally-tensioned rings in 2015 with good effect.

    I'm not aware of them trying those special rings in the 1NZ 1.5L engine. I never looked into the causes of oil consumption on the older 1NZs, but it got fixed a long time ago, so I hope the one you found is new enough.
     
    #3 Leadfoot J. McCoalroller, May 3, 2025
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  4. Pd30242

    Pd30242 Junior Member

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    Here's a collection of videos on the topic. I'm assuming the videos I linked are only referencing the 2NZ though. I guess I kinda assumed the 1NZ had ring problems because of all the oil burning posts I've read. It appears that the 1NZ burns oil because of old valve steam seals & clogged rings while the 2NZ burns oil because of actual "faulty" piston rings.

    "Why do Toyota engines consume oil ? And how to prevent it?"


    "How Toyota fixed oil consumption or oil burning issues, Toyota oil burning problem?"


    "Why do Toyota's burn oil? EASY!"


    "The Consequences of Low Tension Piston Rings"
     
    #4 Pd30242, May 3, 2025
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