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

Head Gasket Replacement, Better or worse MPG or whammy bent rod

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by johnnychimpo, Feb 7, 2021.

Tags:
  1. johnnychimpo

    johnnychimpo Active Member

    Joined:
    Aug 21, 2007
    511
    109
    0
    Location:
    Monterey
    Vehicle:
    2010 Prius
    Model:
    Three
    For those of you who replaced a head gasket and later found you also had a bent rod what were the symptoms of the bent rod?
    For those of you who replaced your head gasket without a bent rod did you get better MPG or worse?
     
  2. Dilbone

    Dilbone Member

    Joined:
    Sep 22, 2020
    76
    58
    0
    Location:
    Northwest Ohio
    Vehicle:
    2011 Prius
    Model:
    Three
    No bent rod here, same mileage so far 2,000mi

    I knew I didn't have a bent rod because I checked each piston height and they were all identical before I put it back together.

    SM-G981V ?
     
    ASRDogman likes this.
  3. Shenine

    Shenine New Member

    Joined:
    Jul 3, 2021
    15
    9
    0
    Location:
    GA, USA
    Vehicle:
    2014 Prius
    Model:
    Two
    Anyone have an answer to this? I was wondering too. @Mendel Leisk ?
     
  4. Mendel Leisk

    Mendel Leisk EGR Fanatic

    Joined:
    Oct 17, 2010
    56,693
    39,237
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    No clue. Try googling:

    symptoms of a bent piston rod
     
  5. privilege

    privilege Active Member

    Joined:
    Mar 17, 2021
    659
    169
    0
    Location:
    Birmingham
    Vehicle:
    2011 Prius
    Model:
    Three
    no one would replace a head gasket without checking piston travel. it at least I HOPE they would check piston travel before replacing a gasket.

    it takes ten minutes to slap an indicator on it and know that tdc is the same, or the connecting rod/bearing is toast.
     
  6. johnnychimpo

    johnnychimpo Active Member

    Joined:
    Aug 21, 2007
    511
    109
    0
    Location:
    Monterey
    Vehicle:
    2010 Prius
    Model:
    Three
    I replaced mine having cold start shake happen only couple of times and noticing coolant being low. I checked piston height travle after I took the head off. I have never done it before and was unaware of hydro lock. In any case I figured if I mess it up i only lose a haed gasket and was prepared financial for a new engine swap. I successfully changed the head gasket but still had issues with the engine. It turned out after all the work somehow a fuel injector got damaged and got stuck open flooding cylinder #4 causing hydro lock not due to the head gasket as I found failed at cylinder one, so I know for a fact the bent rod was caused after the head gasket replacement. Who knew I have never done the head gasket so how would I even know to check for a bad injector. Key here is don't rush the job if it don't work right double triple check everything before you damage your engine. I know we need our cars but take your time it may cost you for rushing.
     
  7. rjparker

    rjparker Tu Humilde Sirviente

    Joined:
    Jun 6, 2008
    8,503
    5,065
    7
    Location:
    Texas Hill Country
    Vehicle:
    2012 Prius v wagon
    Model:
    Three
    This was on your gen4 Frankengen engine?
     
  8. johnnychimpo

    johnnychimpo Active Member

    Joined:
    Aug 21, 2007
    511
    109
    0
    Location:
    Monterey
    Vehicle:
    2010 Prius
    Model:
    Three
    It was a gen 3 engine not franken engine. But yes upgraded to a gen 4. the fuel Injector had a dent right on the tip. I only noticed when I was realigning the timing chain and setting top dead center when it got to the top it squirted a bunch of fuel out of the cylinder. Then I knew.