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random overheating

Discussion in 'Gen 2 Prius Main Forum' started by siskilla, Aug 2, 2018.

  1. siskilla

    siskilla New Member

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    2008 Prius
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    Plug-in Base
    2008 with 87k miles...i hear the noise from the engine bay when i park, the heat blows cold...the triangle of death comes on for seconds at a time with the temp overheat symbol... the check engine came on for the p1121 coolant control valve but went off on its own... so the car runs for weeks at a time without issues, then when i add water/antifreeze, and satisfied bled, it starts overheating...should i change the control valve or is this a bad motor?
     
    #1 siskilla, Aug 2, 2018
  2. M in KC

    M in KC Active Member

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    First off where are you adding your water/antifreeze at? You have two separate cooling loops in your car. One for the internal combustion engine (ICE) and one for the inverter. You should not have to be adding coolant to either system, you have a leak(s) that need to be identified and corrected.

    P1121 is a common failure point on these cars. The fix is replacing the valve if it is suspect or has stopped working.
     
    #2 M in KC, Aug 3, 2018
  3. JC91006

    JC91006 Senior Member

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    The noise you're hearing when you park, it's the pump that gets coolant to your thermos. It turns on for about 10 seconds.

    As for your overheating, I suspect you are not adding coolant/water to the radiator. You have to remove the front engine cover, then you'll see the radiator cap. That's where you fill it.
     
    #3 JC91006, Aug 3, 2018
    edthefox5 likes this.
  4. edthefox5

    edthefox5 Senior Member

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    On this car the overflow tank can show full and the rad can be empty. very strange. Overflow does nothing really.
     
    #4 edthefox5, Aug 3, 2018
  5. siskilla

    siskilla New Member

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    nj
    Vehicle:
    2008 Prius
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    Plug-in Base
    yes im a lil mechanically inclinded.. worked on plenty of other cars, never a hybrid. So i was putting water/antifreeze in the radiator and very other fill, the car would last either (red triangle of death coming on) weeks or few minutes drives. SO the cel came on for the coolant control vallve.. I was happy because i figured that was the issue and cause for my water/antifreeze disapearing over time without a visible pudle. So i replaced the valve, bled as best as possible, now the cel comes on more often when with my old valve it only came on once. ALSO, when i am bleeding the system and adding antifreeze, the fantifreeze is violently shooting back out the radiator when it wasnt doing that before. My question is, did i finally blow the headgasket, should i try the bluedevil route as read in other threads, should i replace any other items.. BTW thermostat was replaced while replacing coolant valve..(thermo looked pretty bad, been thinking that might have been the cause the whole time)...HELP A NEW PRIUS OWNER
     
    #5 siskilla, Aug 14, 2018
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