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Intermittent Hi Temp Light

Discussion in 'Gen 3 Prius Main Forum' started by Stephen Auciello, Jul 23, 2022.

  1. Stephen Auciello

    Stephen Auciello New Member

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    Hey folks greetings, I’m new in these here parts….have a 2012, hi temp light coming on occasionally, almost every time I get on highway, and only for a few moments. Seems to be connected (sometimes) to accelerating and/or going uphill, and usually when A/C is on. I did have the coolant level low for a while, in my negligence, but recently topped it off and (I think) bled out the air by running in maintenance mode for two fan cycles. Recently one of the times the light came on while driving on freeway, I stopped and popped the hood, but all seemed normal, fluid wasn’t overflowing or boiling and engine didn’t feel hot; got back in and light was off for the rest of my 10-15 minute trip.
    Any ideas??
    Thanks much for your time!!!
     
    #1 Stephen Auciello, Jul 23, 2022
  2. JC91006

    JC91006 Senior Member

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    How many miles on your car? One of the symptoms of loss coolant is a head gasket failure.

    You should try to bleed the air out of the system again and top off if needed
     
    #2 JC91006, Jul 23, 2022
  3. ASRDogman

    ASRDogman Senior Member

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    Also check the radiator. Make sure it's not blocked.

     
    #3 ASRDogman, Jul 23, 2022
  4. PriusCamper

    PriusCamper Senior Member

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    Let us know if you hear air being sucked in when you open the coolant reservoir?
     
    #4 PriusCamper, Jul 23, 2022
  5. Stephen Auciello

    Stephen Auciello New Member

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    About 165K (I’m out of town at moment)…that makes sense although for a long time quite simply i failed to monitor the coolant level….

    How to do that? It’s not the type that has a cap, as you’re probably aware….

    I’ll check for that next, thanks!
     
    #5 Stephen Auciello, Jul 24, 2022
    Last edited by a moderator: Jul 24, 2022
  6. ASRDogman

    ASRDogman Senior Member

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    The radiator, and ac condensor. Make sure the fins are not clogged with dirt, branches, etc.

     
    #6 ASRDogman, Jul 24, 2022
  7. Noahdoge

    Noahdoge Active Member

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    Sounds like you might need to replace the ICE water pump. They are known to start sticking and not work properly at high mileage. It’s expensive to get done at the dealership but you can buy oem from Toyota parts online for $200 and do yourself or have your mechanic do it. You will also need 2 gallons of Toyota oem antifreeze as well. Good opportunity to do the inverter coolants as well. Definitely clean your egr system with your mileage if it hasn’t been done before. Refer to @Mendel Leisk signature on that.
     
    #7 Noahdoge, Jul 25, 2022
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  8. Stephen Auciello

    Stephen Auciello New Member

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    I did notice air sucked in when opened reservoir cap……checked right after I parked so engine was warm, not sure if that matters ….
     
    #8 Stephen Auciello, Jul 25, 2022
  9. Stephen Auciello

    Stephen Auciello New Member

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    Got it, I thought you meant clogged inside…
     
    #9 Stephen Auciello, Jul 25, 2022
  10. Stephen Auciello

    Stephen Auciello New Member

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    So that’s what I was thinking as well and was ready to do, but the light is not super erratic, but consistently coming on usually within a few minutes of starting to drive, and then turning off and staying off…
     
    #10 Stephen Auciello, Jul 25, 2022
  11. ASRDogman

    ASRDogman Senior Member

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    If you search ebay, you can find just the impellor. About $40.
    That's what I did with mine...
     
    #11 ASRDogman, Jul 25, 2022
  12. Stephen Auciello

    Stephen Auciello New Member

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    Nice thanks!
     
    #12 Stephen Auciello, Jul 30, 2022
  13. PriusCamper

    PriusCamper Senior Member

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    That sucking sound when you open the reservoir lid means you're losing coolant. Usually this combined with engine misfire codes is confirmation for blown head gasket, but in your case it might only mean a leak related to overheating/pump failure.
     
    #13 PriusCamper, Jul 30, 2022
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