1. Attachments are working again! Check out this thread for more details and to report any other bugs.

My experience on changing my Gen three Prius head gasket

Discussion in 'Gen 3 Prius Main Forum' started by CapnBio, Aug 6, 2024 at 3:04 PM.

  1. CapnBio

    CapnBio Junior Member

    Joined:
    Nov 2, 2016
    24
    10
    0
    Location:
    US
    Vehicle:
    2014 Prius
    Model:
    Three
    Today I'd like to outline my experience on changing the head gasket of my 2014 Prius. It was quite the venture and it was definitely a good challenge, and who doesn't like a challenge from time to time?

    One day I had come here for help and guidance and that guidance was one to take. I received a bunch of help from all the good fellows here on the forum and I couldn't be happier, but when I did those things my problems lead to a not so deep rabbit hole so it was manageable since it's all here. But it ultimately lead me down the road to replace a head gasket. Turns out it was the problem the entire time, as the gasket was never replaced and it was the original from the factory (very likely). It seemed to be pretty chewed up (no "protective" paint layer on a lot of the old gasket) from the coolant chewing through it.

    My car did have over 175k miles on it, so I'm my thought process said it was absolutely time to change it.

    The main reason why I changed the head gasket:

    I was in traffic one day and it's stop and go traffic, of course the engine started rattling violently and I'm like well crap this isn't good and it does this only after having the engine stopped for a good several seconds and the engine finally threw a misfire in cylinder 2. It mainly stayed just fine while the ICE ran all the time with no shaking and the shaking only lasted a quick second before it was back to normal. So I thought "welp time to go get home and see what's up". I decided to let the pressure loose in the coolant reservoir and it smelled like gasoline was mixed in there and that lead me to this venture.

    While getting prepared since I already made the decision to change it myself, I watched many YouTube videos on changing the gasket and I bought a few tools (torque wrench, angle meter, and special bits) and I already had a regular socket set with borrowing an impact driver as well, so I began taking everything apart. When I got to the gasket, it was a disaster in my eyes and couldn't believe how bad it was and the failure point in where it was leaking into cylinder 2. I resurfaced the head at my local head cylinder head shop for a couple hundred bucks for my piece of mind as they tested for pressure leaks, cracks, and resurfacing.

    Putting everything back together
    I put the head back on with a new fel pro gasket and new head bolts, everything was easy since it was a reverse of when you took it apart, and labeling baggies with where everything goes (ie. bolts and nuts) was a life and time saver!

    Before starting the car
    I made a couple mistakes removing the harness from the engine and other bits and may have pulled a bit too hard and that's when I learned to be extra careful with anything electrical. I had to resolder the connector the camshaft sensor and cylinder 1 injector.

    As the camshaft the car will not start (even though it's on ready mode but it'll throw you a code at least), and any fuel injector it will idle really rough (not violently shaking) and the fuel coming out of the tailpipe is really rich smelling. Which was my experience on this whole ordeal.

    In conclusion be careful with your harnesses and connectors! It'll save you a few hours of troubleshooting. I fortunately have emissions testing in Georgia so I couldn't pass it with a head gasket leak, so time for testing again! I made sure with a odbii reader that all permanent codes have disappeared after almost 50 miles of driving.

    Thanks for all the help PC forum!
     
  2. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    109,096
    49,588
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    Great write up, congrats!
     
  3. ForestBeekeeper

    ForestBeekeeper Active Member

    Joined:
    Sep 19, 2011
    721
    276
    0
    Location:
    Maine
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Premium
    I am glad it all worked out okay.