Best way to diagnose a possible head gasket leak?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Sterlingarcher6969, Mar 27, 2022.

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  1. Sterlingarcher6969

    Sterlingarcher6969 Junior Member

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    Hi everyone!

    Couple months ago I was watching a video on head gasket to see how involved it was. I remember the guy saying if your coolant goes low you probably have a head gasket problem, well.. yesterday I was giving the engine bay of my 2014 a clean and noticed both the inverter and engine coolant were both at or very near the L marker. (I'd say the engine was just barely warm to the touch of that matters)

    I bought my prius last year around 128k miles and I just passed 148k I've had no engine problems yet and knew head gasket was a possibility because it's a gen 3.

    Anyway I've done some googling and as far as I can tell I have 2 options. I can go to my nearest NorCal hybrid place($140) and ask them to look at it
    Or get a sample of my oil and have it analyzed for Any coolant ingress (like $90) and will tell me more than just that about the state of the engine.

    If any of you in the bay area have a hybrid shop suggestion (anywhere in-between concord and Sacramento)
     
    #1 Sterlingarcher6969, Mar 27, 2022
  2. rjparker

    rjparker Tu Humilde Sirviente

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    Normally a gen3 head gasket leak does not get into the oil. The coolant temporarily fouls out the spark plug causing a misfire which causes a severe metal to metal rattle and shake until the plug clears. Otherwise you may have a coolant leak somewhere else. A borescope inspection of the cylinders is useful if it is rattling. The piston is likely to be steam cleaned. I would check with Gasketmasters.


     
    #2 rjparker, Mar 27, 2022
  3. Sterlingarcher6969

    Sterlingarcher6969 Junior Member

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    So I should wait for a misfire code? The engine does not rattle and sounds the same on startup as when I bought it at 128k
     
    #3 Sterlingarcher6969, Mar 27, 2022
  4. rjparker

    rjparker Tu Humilde Sirviente

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    Need to find the coolant leaks. Overheating the engine is a guaranteed engine failure. Even with a hg leak, it may not code because it clears too fast.
     
    #3 rjparker, Mar 28, 2022
  5. Sterlingarcher6969

    Sterlingarcher6969 Junior Member

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    I'll keep an eye on the engine temp in hybrid assistant. I've got some more coolant on the way to top it off. I'll give the engine bay a thorough cleaning so it will be easier to spot the leak as well.

    It's got to be a really small one though because the last time it was topped off was before November last year
     
    #3 Sterlingarcher6969, Mar 28, 2022
    Last edited: Mar 28, 2022
  6. rjparker

    rjparker Tu Humilde Sirviente

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    You should go years without losing coolant. When the temp light comes on you must pull over safely and have it towed. It is an all aluminum engine and won't take much before fatally warping.
     
    #4 rjparker, Mar 28, 2022
  7. Sterlingarcher6969

    Sterlingarcher6969 Junior Member

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    Ok will do. I'll keep a very close eye on it. I did get into an accident on that side last October. it was a motorcycle going like 20 and hit the front right fender just Infront of the wheel. The repair guys could have missed a leak... They did forget to put in the right front blinker bulb AND new washer fluid reservoir.
     
    #5 Sterlingarcher6969, Mar 28, 2022
    Last edited: Mar 28, 2022
  8. Sterlingarcher6969

    Sterlingarcher6969 Junior Member

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    this is a hybrid assistant generated graph of a 50 mile delivery run from the 15th of this month.
    I guess the engine does get pretty hot and did infact hit 194f although it was for 8 minutes

    The times where it cooled down where where I had the car off waiting for a delivery.
     
    #6 Sterlingarcher6969, Mar 28, 2022
  9. Paladain55

    Paladain55 Active Member

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    This is what I use when we buy shitbox vehicles. You just need to make sure to put the prius in diagnostic mode and rev it up to really get some pressure into the cooling system (if you do indeed have a head gasket leak). So like a steady rev at 3500 rpm for a couple seconds.

     
    #7 Paladain55, Mar 29, 2022
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