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blown head gasket P0301 P0302 P0300 ?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Alain D, Aug 11, 2024 at 11:50 AM.

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  1. Alain D

    Alain D Junior Member

    Joined:
    May 23, 2019
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    Location:
    Santa Cruz, CA
    Vehicle:
    2014 Prius
    Model:
    II
    Background:
    * 2014 Prius with 205k
    * bought the car at 150k (was uber) and did right away the EGR cooler (quite clogged)/pipe/valve, new PCV valve and added an Oil Catch Can to prevent future cleanups, cleaned intake manifold (had pool of oil) 4 small holes (also clogged) using @NutzAboutBolts videos
    * spark plugs were changed at ~140k (iridium bosh) by prev owner
    * car never burns any oil (I believe 2014 has fixed ring redesign), changed every 5-6k, and I get maybe half a finger worth in the OCC (milky smell like gas+oil)

    What happened
    * got engine light check for P0301 cylinder 1. cleared it and came back but didn't feel misfire
    * one morning started the car and bad shaking for 15+ sec, strong smell of gas in the exaust

    since EGR should still be clean and newer spark plugs (and unlikely coil going bad especially now that it's 2 cylinder) I thought maybe fuel injector are dirty (gas smell above) so I poured a bottle of Techron Fuel cleaner into my 7gallon filled tank (didn't have luxury of mostly empty tank unlike directions, and syphoning gas didn't work). Decided to drive it one more day about 70 miles.

    * mostly cylinder 1 (oh oh) but also occasionally getting cylinder 2, and even a P0300 (multiple misfire)
    * notice the coolant appear 2" low (keeping an eye now) but not driving the car anymore since it might be a HG instead of dirty injectors ?
    * the few times I noticed shaking was at low rpm or startup

    Read here combustion leak detector (blue -> yellow) might not work on prius so didn't order one. have not checked pressure in coolant tank yet. Thinking of using a boriscope to see inside cylinder 1 and see if I see any coolant but wondering if there something easier I should try first.

    I did a big preventive maintenance with the EGR to prevent this from happening 50k ago and here am I now. I drive an EV now so this is my daughters car, but I don't know I'll ever buy gas car again... :(
     
    #1 Alain D, Aug 11, 2024 at 11:50 AM
    Last edited: Aug 11, 2024 at 11:56 AM
  2. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
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    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    And about 100k too late; head gasket failing.

    A third gen for sale with 150K is almost guaranteed to be a dumped-by-owner scenario. Any evidence of stop-leak product?
     
    #2 Mendel Leisk, Aug 11, 2024 at 12:11 PM
  3. Tombukt2

    Tombukt2 Senior Member

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    Don't fix it get your daughter a realistic car for a young person whatever that might be a Chevrolet Aveo a generation 2 a Chevy bolt maybe there's a lot out there to mull over that's for sure But don't waste time fixing the G3 seriously you'll just be fixing on it all the time moving forward if you enjoy doing that sort of thing then by all means have at it your kids going to want to drive not wait for repairs generally speaking.
     
    #3 Tombukt2, Aug 11, 2024 at 12:47 PM
  4. rjparker

    rjparker Tu Humilde Sirviente

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    Vehicle:
    2012 Prius v wagon
    Model:
    Three
    Good advice from Tom. One company near you who has been making a living changing Prius head gaskets for years, now recommends preemptive hg changes before they blow and rebuilt engines after.

    If the car is excellent otherwise and already had a brake booster replacement, you might consider a rebuilt engine from Hybridpit in the LA area.
     
    #4 rjparker, Aug 11, 2024 at 1:11 PM
  5. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
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    Vehicle:
    2010 Prius
    Model:
    Touring
    That’s the easy method. Do it first thing in morning, day after a drive. Or figure out a way to pressurize the engine coolant circuit, look for coolant tears starting at the head gasket. You’ll need a side viewing boroscope.
     
    #5 Mendel Leisk, Aug 11, 2024 at 1:38 PM
  6. Alain D

    Alain D Junior Member

    Joined:
    May 23, 2019
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    Location:
    Santa Cruz, CA
    Vehicle:
    2014 Prius
    Model:
    II
    I didn't think about that... but 55k later seems like a long time for that to old up. 150k/10y is when CA hybrid battery warranties expires (I did throuhgly tested the battery with Dr prius app and rejected other cars) so figure that was why, and price reflected that. I assume the only way to know will be to examine the HG if/when I replace it...

    Don't have sideway boroscope, only down so will have to wait to drip down :)

    Didn't know about brake booster issues... will have to research that before spending time or $$ replacing HG. She loves her prius (I drove it tons before getting an EV when she was in College/abroad) and the gas mileage (~44mpg) is prety close to my Tesla (electricity is very expensive in Cali).
     
    #6 Alain D, Aug 11, 2024 at 2:33 PM
    Mendel Leisk likes this.
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