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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.

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  1. johnnychimpo

    johnnychimpo Active Member

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    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

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    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 ?
     
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  3. Shenine

    Shenine New Member

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    Anyone have an answer to this? I was wondering too. @Mendel Leisk ?
     
  4. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    No clue. Try googling:

    symptoms of a bent piston rod
     
  5. privilege

    privilege Active Member

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    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

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    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

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    This was on your gen4 Frankengen engine?
     
  8. johnnychimpo

    johnnychimpo Active Member

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    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.