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Gen3 engine replacement with Gen4

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by SteveLee, Dec 25, 2019.

  1. SteveLee

    SteveLee Active Member

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    My son just pulled his 2012 Prius engine (blown head gasket for about a year so it was a mess) out the top and leaving the trans in place. Has now set in a 2017 replacement purchased from across the country. Still in the process of connecting everything in his spare time but wow, I am very proud of him since he had little mechanic experience. But he was motivated, being a poor college student, and refused to give up on his Prius. He used the Youtube series on replacing the Prius engine for direction. Just wanted to mention it here to encourage others.
     
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  2. chronon

    chronon Active Member

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    i did an engine replacement with help of fam, alot of help from a few online people on here, some utube and the manual - i want to tell u he told me dont pay antention to the toy tech manual, they will have u do stupid things like take the dash out , essentially they have u spending twice as much time as u need to to do get the job done - this was an 05 , i think an 06 engine replaced it , we spent about 80 manhrs , about 2 weeks total working about every day , quotes from mechanics were around $1000 on up , and most mechanics simply didnt want to fool with high V, for fear of electrocution and perhaps from not being trained/qualified in the new tech -
     
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  3. tankyuong

    tankyuong Senior Member

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    Hope it’s possible with a 2017 engine
     
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  4. bisco

    bisco cookie crumbler

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    how many miles on her?
     
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  5. chronon

    chronon Active Member

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    should be with same generation, if your puling a bigger engine out 6of a newer gen car to put into an older gen car,
    there could be issues ..
     
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  6. SteveLee

    SteveLee Active Member

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    His has 180k. The donor engine has about 40k
     
  7. SteveLee

    SteveLee Active Member

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    So do we. Based on the video series it works, though there are some relatively minor alterations like changing the motor mount to the old one, and a few others. The motor mount was one of the few things not covered in the video and became apparent in the installation. But it was a direct bolt-on replacement. So far, so good.
     
  8. SteveLee

    SteveLee Active Member

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    BTW, the dealer wanted $7,000 to replace the engine.
     
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  9. bisco

    bisco cookie crumbler

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  10. bisco

    bisco cookie crumbler

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    what is the history? has he owned it since new? ever clean the egr?
     
  11. SteveLee

    SteveLee Active Member

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    Edited History: He bought the car with about 130k miles on it. About 160k it started making "noises", like misfiring or a cylinder not firing, running very rough. At first, it was for very short periods but got increasingly worse over the next months, more often and for longer periods. He did finally learn how to remove and clean the egr cooler and valve. But by that time I think the damage was done, he was losing coolant. By this time he had replaced the water pump which may have been the cause of overheating and blowing the head gasket. He also replaced the plugs and coils, hoping they may be the issue. But the symptoms just continued getting worse until it finally wouldn't run. That's when he had to do something next level.
     
    #11 SteveLee, Dec 26, 2019
    Last edited: Dec 26, 2019
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  12. Mendel Leisk

    Mendel Leisk Senior Member

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  13. SteveLee

    SteveLee Active Member

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    Yes, that was for a new Gen3 engine. I think it was a price stating they did not want to do it, but if you insist this is what it will cost you. The used donor engine with about 40k miles was about $1,100 with shipping from CA to NC.

    Edit: The used replacement engine also came with the intake manifold which may have to be replaced with the old one. Not sure at this point.
     
    #13 SteveLee, Dec 26, 2019
    Last edited: Dec 26, 2019
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  14. Raytheeagle

    Raytheeagle Senior Member

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    When he pulled the water pump, did he investigate it:whistle:?

    I’ve seen a couple of pumps show signs of failing (I’ve examined 4 of them), and the impeller seems to begin rubbing on the containment shell:cool:.

    That extra resistance can cause the rpms to not be right, leading to other unintended consequences ;).

    If he still has it, try to spin it by hand and inspect the impeller:).

    Curious minds would like to know if the specimen is available(y) .
     
  15. SteveLee

    SteveLee Active Member

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    Yes, exactly. That is what we noticed when we compared the old one with the new one. The impeller did not turn as freely, there was some friction resistance when turning it by hand. I understand this is not an uncommon finding when there has been a blown head gasket. There was never any indicator on the dash of overheating but at some point he told me the temp sensor wire had been disconnected. I hate to think the previous owner or dealer would have disconnected that to avoid replacing the pump. That would have been a relatively easy fix to prevent ruining the engine. The difference between a few hundred and multiple thousands of dollars.
     
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  16. SteveLee

    SteveLee Active Member

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    A little help here. Since the flywheel and damper of the Gen4 engine has to be replaced with that of the Gen3 engine, what if any significance is the arrow on the flywheel?

    Edit: Any suggestions on a free service manual?
     
    #16 SteveLee, Dec 31, 2019
    Last edited: Dec 31, 2019
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  17. seeker311

    seeker311 Junior Member

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    Howdy. I am literally at this step. Swapping the flywheels / dampers and already removed them without marking them as ragingfit video suggests. I don't see any obvious alignment identifiers except the arrow on the flywheel. the damper doesn't seem to have alignment marks either. Both parts are just spinning in a circle so I wouldn't think there are any required alignment marks for timing, etc. actually that is a false statement. there are timing marks, but i believe they are on the crack shaft pully, so we should be good. I'm going to try and remember how they were and keep them together and fingers crossed, because if there are required marks, it's gonna suck to remove the engine and realign, unless it can be done without separation.