2012 Prius V JDM engine replacement questions

Discussion in 'Prius v Care, Maintenance and Troubleshooting' started by Soundquest, May 29, 2026 at 5:48 PM.

  1. Soundquest

    Soundquest New Member

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    2012 Prius V -- existing engine has the typical head gasket issue. 240K miles on it so I would say we did pretty well. Considering a 60K mile JDM engine replacement (will be performing myself -- I have done engine replacements before on other vehicles far more complex than this so not afraid and not inexperienced). So my question is, what other items should be replaced/serviced when I do the replacement besides the EGR valve, plugs, worn belt drive components if applicable, valve cover gasket, TB cleaning, etc? And what else (in the engine bay, so not on the engine) should I service while I have all that room when the engine is out? Lastly, most videos up on this engine replacement do not show the actual disconnecting process for the transmission, but it is my understanding it is very straight forward and very accessible; are there any important details or tricks I should be mindful of? Lastly -- the batteries (hybrid) are showing good health still and we have no issues with the current transmission, which I am surprised at. Has anyone else on here reached this mileage without hybrid battery issues and without transmission issues?
     
    #1 Soundquest, May 29, 2026 at 5:48 PM
  2. rjparker

    rjparker Tu Humilde Sirviente

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    No one has a transmission or belt drives on a gen3 Prius.

    Almost no one ever had an ecvt transaxle with motors problem.

    Plenty of diyer's ruin the ac compressor.

    Some screw up and change good oem parts with aftermarket.

    Which is more advice than I usually give to those who won't even share their location. Others will suggest not doing it, rebuilding the JDM and or changing all bolt ons.
     
    #2 rjparker, May 30, 2026 at 12:06 PM
    Last edited: May 30, 2026 at 12:25 PM
  3. Soundquest

    Soundquest New Member

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    Excellent. Fair reply. Sandpoint :). Sage advice and I appreciate it.
    < slides $100 bill over the counter -- "what else do you have for me?" >
     
    #3 Soundquest, May 30, 2026 at 6:29 PM
  4. rjparker

    rjparker Tu Humilde Sirviente

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    Cover the compressor connectors to avoid coolant entry.

    Make sure its a JDM by verifying the engine tag and injectors are different.

    Verify JDM distributors compression tests and find the best engine. Some were sold in Japan as late as 2021. Install it quickly to maximize the warranty.
     
    #4 rjparker, May 31, 2026 at 1:02 AM
  5. Soundquest

    Soundquest New Member

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    Many thanks. And if you were to choose a YT video that demonstrates this operation the most thoroughly and with best practices, what would you choose? Foreign Engines would be the outfit we are likely going to use (they are local). What do you like to see for compression numbers on this engine? I had no idea they used different injectors on the JPN version -- what's different about them?
     
    #5 Soundquest, May 31, 2026 at 5:03 PM
  6. rjparker

    rjparker Tu Humilde Sirviente

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    Tan injectors
    X2ZR-W20 on the engine
     
    #6 rjparker, May 31, 2026 at 9:03 PM
  7. ChapmanF

    ChapmanF Senior Member

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    What is different about the engine that makes the different injectors appropriate?
     
    #7 ChapmanF, May 31, 2026 at 9:54 PM
  8. rjparker

    rjparker Tu Humilde Sirviente

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    The used in Japan engine has a different model code and tan injectors. Many thousands used successfully in the US. Unknown differences but useful for identification vs US salvage. Some so called JDM engines are actually US salvage.


    IMG_1606.jpeg IMG_1609.jpeg
     
    #8 rjparker, May 31, 2026 at 11:11 PM
  9. Mendel Leisk

    Mendel Leisk MMX GEN III

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    Good series of videos on engine swap, in a somewhat obscure location:

    Ragingfit’s engine swap

    it’s complicated some by the donor engine being 4th gen, but the basics of the swap are all there.
     
    #9 Mendel Leisk, Jun 1, 2026 at 8:39 AM
  10. rjparker

    rjparker Tu Humilde Sirviente

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    You don't want to do a gen4 swap because its not really a gen4 but a frankengine using parts of a gen3 for fit, plus wiring and cooling mods.

    Its far better to get a rebuilt engine if like new is your goal with updated pistons and rings. Such as the Hybridpit Rebuilds Gold package.

    If Gen4 cylinder cooling engineering is the goal then Hybridpit has their own frankengine solution with a specially modified head gasket to allow better cooling when combined with gen3 parts.

    Any of these solutions will be 3 to 5 times more expensive than a JDM.
     
    #10 rjparker, Jun 1, 2026 at 8:49 AM
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