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2012 rough start (have searched till infinity)

Discussion in 'Gen 3 Prius Technical Discussion' started by N2MPG, Apr 19, 2022.

  1. N2MPG

    N2MPG Junior Member

    Joined:
    Sep 10, 2013
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    Location:
    Radford Va
    Vehicle:
    2012 Prius
    Model:
    Two
    2012 Prius II 249k Miles.
    Well... For some confusing info today.
    Early November I was out driving city driving start and stops.
    At a light when the ice kicked in it had the rough running I see posted everywhere. Few seconds later it stopped and I got the car home.
    I got paranoid and didn't have head gasket money.
    Next I got busy and have now recently taken it to a shop. I jumped the car to get it started and the rough running was there, popped off the coolant res tank kid and it stopped. My shop is literally 4 doors from me.
    They get the car, were checking on head gasket failure. No milky oil, no smoke, pressures in the reservoir was normal and... Here's the kicker... It didn't do it to them at all. Today I picked it up with the intention of pulling and cleaning the EGR, pcv, and intake manifold... Runs fine, great even.
    I start and stop a couple dozen times ensuring the ice stopped and restarted... Nothing.
    Coolant in res was low, shop filled it with Toyota coolant.
    No problems today. I started and stopped with and without the AC and heat in in case it was something to that.

    Anything I'm missing in my though process... Why on earth would it suddenly be running fine.

    Also happened to notice I still have the original 12v battery

    I know this has been visited and revisited .. I didn't see anybody who's problems just went away.

    Any way to check the water pump without pulling it?
    Any other tests that may diagnose?
    My coolant was pretty low when it started...and is full now. Could that have been an issue?
    Also as far as I can remember I used to run torque all the time and never noticed temp issues.
    Arrggggg
     
    #1 N2MPG, Apr 19, 2022
  2. Tombukt2

    Tombukt2 Senior Member

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    Location:
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    Vehicle:
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    Model:
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    Your clue is probably the coolant was down that would be mine now pull the number two plug smell it stick your tongue on it if you're brave enough taste coolant bingo do it with all four plugs if you like that's probably what I would be doing but when I got to two and it tasted like coolant I would know I could pretty much stop and hasn't gotten bad enough to set the light yet so but sounds like you're on the right road I just finished with this
     
    #2 Tombukt2, Apr 19, 2022
  3. ASRDogman

    ASRDogman Senior Member

    Joined:
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    Location:
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    Vehicle:
    2010 Prius
    Model:
    Two
    DO NOT TASTE THE COOLANT!!!! IT IS POISONOUS! IT WILL KILL YOUR LIVER!
    AND THERE IS NO TREATMENT FOR THAT!

    If you've never cleaned your cooler, or intake manifold, that could be the reason your head
    gasket has failed, or is failing. How the car is driven will give you different results on when
    you get the rough idles....

    From what I've read, it's extreamely rare that there will be coolant in the oil. The coolant seeps
    through the failing head gasket between the #1 and #2 cylinders.

    You're 12v battery could be back. You gave no information about it, just that you had to jump the car. ???
    If you have find a technician that works on hybrids, that would be your best option.

    If you are mechanically handly, you can change it yourself with only having to purchase a few speacial tools.
     
    #3 ASRDogman, Apr 19, 2022
    cowgurlprius likes this.
  4. N2MPG

    N2MPG Junior Member

    Joined:
    Sep 10, 2013
    30
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    Location:
    Radford Va
    Vehicle:
    2012 Prius
    Model:
    Two
    Well 12v was dead because I left the car for a couple months.
    But starts now ..
    My next action is to pull the intake manifold and EGR cooler pipes etc to clean them ..

    Also.. when the ice turns off there has been a sort of water noise from the dash. Like a fountain turning off if that makes sense.
     
    #4 N2MPG, Apr 19, 2022
  5. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
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    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    With 249k and no EGR cleaning to date, I’d find someone who can do leak-down test and boroscope inspection of the cylinders, to determine head gasket condition. EGR cleaning is good, but way overdue.
     
    #5 Mendel Leisk, Apr 19, 2022
    cowgurlprius likes this.
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