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Very [loud] whining vacuum sound, super fast overheat, what happened?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Travisfixingaprius, Sep 29, 2022.

  1. Travisfixingaprius

    Travisfixingaprius Junior Member

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    I have been dealing with some overheating issues on my 2012 Prius recently and was told that it might be the thermostat because at the same time while overheating the passenger side heat went out and then all the heat went out.

    The other night while driving at 40mph I noticed that my overheat light came flashing on. and then as I got closer to home in that 5 minute span it was overheating at 20mph. And then it became 5mph.

    It went as followed:
    1. Car overheating all of the sudden
    2. Car overheating excessively with solid overheat light even at declining speed.
    3. Weird sputter of a vacuum.
    4. Vacuum sound gets very very loud and doesn't go away.
    5. Now upon starting vacuum sound is running.

    The whining sound I have never heard. I thought the coolant maybe went low and so it was sucking like a vacuum for coolant. Well, I got out of the car to check the coolant and it almost bursted out as usual. The top hose for the coolant area was super cold and its not usually like that either when its been running for a while.

    I attached a few videos to hear whats going on. It's so loud I cannot pinpoint exactly what it is. It's coming more from the left side of the engine bay where the water pump is.

    First video shows the car starting and the sound appearing. Second video I did a sound walkthrough with my phone to see if it picked up more sound from a given area.

    vid 1
    https://youtube.com/shorts/UWZ32Gs0R-M?feature=share

    vid 2
    https://youtube.com/shorts/bCv2DWcqZaE?feature=share


    If I can find anything I will update this post so others can learn from it as well.

    Update 1:
    I replaced the thermostat before creating this thread. That was the theory of what was going on but did not fix the noise. Maybe it fixed the heat but that loud sound is the goal to fix here. And in fact the thermostat was stuck closed.
     
  2. TMR-JWAP

    TMR-JWAP Senior Member

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    Trying to figure out if this is a joke or not.....
    Has the thought of a failed water pump been looked into....
     
  3. Travisfixingaprius

    Travisfixingaprius Junior Member

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    that’s what I have been trying to make sure is going on.

    I don’t have a lot of cash on hand so I wanted to make sure that this was the issue before I start buying more parts that don’t fix the issue.

    Thank you for the input.
     
    #3 Travisfixingaprius, Sep 29, 2022
    Last edited: Sep 30, 2022
  4. ChapmanF

    ChapmanF Senior Member

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    A person might plug in Techstream, or another scan tool that supports active tests, and with the car sitting in IG ON with the engine off, tell it to activate the water pump, and listen for anything sounding familiar.

    There's a thread where mr_guy_mann has reviewed a bunch of scan tool apps, some of which have active test functions. The thread is specific to Gen 2, but probably is a good enough place to start looking for what might work on a Gen 3.
     
  5. Travisfixingaprius

    Travisfixingaprius Junior Member

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    Update: Bought a used water pump from another Prius being parted out.

    I think that is water pump is bad as well. I hear some rattling with it while the car engine is idle and the engine is not running (only electric).

    So the whiny pitch was still intermittent while driving. I figure if this is a bad water pump it probably isn't going to fix the issue either.

    I have my car running in maintenance mode with it on a hill to see if their is air bubbles in the coolant.

    Well as I sit here I hear some loud swish/knock and then suddenly the heat comes back on for just a little bit, and then it goes back to cold.

    The sound is coming from the firewall area from what it sounds like. So maybe the heater core is clogged?? While I am typing I just heard another burst and then the heat came back on for a sec with a lot of heat and then back to lukewarm temp.
     
  6. Travisfixingaprius

    Travisfixingaprius Junior Member

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    Update:

    The car seems to go back to cold air after sometime. If I have the coolant cap taken off and the car running in maintenance mode the heater will blow very cold air and the. I hear a POP/FLUSH sound coming from the firewall nearby the feet area where the heater core tubes are at.

    If the coolant cap is on, the coolant flush sound will not happen. It only happens when the coolant cap is off.
     
  7. ASRDogman

    ASRDogman Senior Member

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    Did the impeller move easily in either pump? That seems to be what fails.
    It starts to swell, and you'll see it.

    You need techstream to test the pump to see if working correctly.
    There's not really a reason the heater core would be clogged. Unless you put something in the coolant.
     
    #7 ASRDogman, Oct 2, 2022
    Last edited: Oct 2, 2022
  8. Mendel Leisk

    Mendel Leisk Senior Member

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    What’s the miles on it, and have you had it since new (know it’s history)? Just wondering if a stop-leak product might be in there.
     
  9. ChapmanF

    ChapmanF Senior Member

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    I just confirmed yesterday there's an easy non-Techstream way to check the water pump. If the engine is warmed up, and you turn the car off, then back only to IG-ON (not READY), and set the heat for the HI temperature, it will run the water pump to circulate the residual hot coolant through the heater. That gives you an easy way to listen for the water pump sound not competing with other engine sounds, and you don't need Techstream to do it.
     
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  10. CR94

    CR94 Senior Member

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    Wouldn't that be the same as the sound heard if one simply parks and gets out to listen with the warm engine still in READY?
     
  11. ChapmanF

    ChapmanF Senior Member

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    It would be, if the engine has stopped, and if your HVAC settings are calling for enough heat to force the water pump to run.

    The thing I confirmed yesterday was simply that you can switch from READY to IG-ON and the same HVAC settings will still run the water pump the same way, and now you know you won't be distracted by other READY-mode sounds, the engine unpredictably starting, etc.
     
  12. Travisfixingaprius

    Travisfixingaprius Junior Member

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    I had used Bars and Leaks before.
     
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  13. Travisfixingaprius

    Travisfixingaprius Junior Member

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    Since 80k miles I’ve owned it. Right at 150k the car started experiencing symptoms of bad head gasket so I did use a sealer a few months ago.

    That’s the theory of a heater core needing to be flushed.
     
    Mendel Leisk likes this.
  14. ASRDogman

    ASRDogman Senior Member

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    That's probably one of your problems.....
    Nasty stuff!
    But you need to take car of that head gasket....

     
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  15. Travisfixingaprius

    Travisfixingaprius Junior Member

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    Update:

    Flushed heater core and nothing unusual came flowing through it. Flowed perfectly so I guess that’s not the issue either.
     
  16. Travisfixingaprius

    Travisfixingaprius Junior Member

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    Update:

    For some reason there is something about taking the radiator cap off, and then pressing the acceleration so the car hums a bit.... well after 10 minutes of doing that all the heat comes back fully. I was able to get the car back on the road up to 60mph and then BOOM overheating and all the heat just disappears again.
     
    #16 Travisfixingaprius, Oct 3, 2022
    Last edited: Oct 3, 2022
  17. ASRDogman

    ASRDogman Senior Member

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    Did you flush the radiator? And the whole system???
    Have you used Techstream to test the pump? Maybe the wiring to the pump?
    It's a simple system. Radiator, heater core, water pump, hoses, thermostadt, cooling fans.
    (are they functioning?)
    Something is clogged, or stuck. Maybe thermostadt?
     
  18. Travisfixingaprius

    Travisfixingaprius Junior Member

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    - replaced thermostat
    - Flushed heater core
    - Replaced water pump


    When I take the radiator cap off and let the car run with the heat on in maintenance mode the heat will return after about 10 minutes because it gets ice cold and then I hear some fast sloshing sound really fast like a pipe burst and then it restores. But after a minute or so it returns back to being cold and repeats the same process.
     
  19. Travisfixingaprius

    Travisfixingaprius Junior Member

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  20. ChapmanF

    ChapmanF Senior Member

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    And there is no similar sound in IG-ON with the engine warm and the heater set to HI ?