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Whirling sound at start-up

Discussion in 'Gen 4 Prius Technical Discussion' started by Ella, Feb 23, 2018.

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  1. Ella

    Ella Junior Member

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    First of, apologies if this is already a thread somewhere! I am a total Prius noob, having owned my 2017 Prius 2 for only 4 months. I've noticed in the mornings when I turn on my car, a whirling sound occurs, almost like a large fan (if I had to compare it to something, it sounds vaguely like the fans on a plane right before take-off...obviously not as loud). I'm not sure if this has to do with engine start-up or anything; temperatures in the morning range from 33-45F, but I still hear this sound when I'm going home and temperatures are 50-65F. Any ideas? I'll try to get a video/sound clip to supplement this post. Thanks for your time!
     
    #1 Ella, Feb 23, 2018
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  2. RRxing

    RRxing Senior Member

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    There is a brake booster pump that typically makes this noise at startup, and at some other times. Completely normal...
     
    #2 RRxing, Feb 23, 2018
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  3. Ella

    Ella Junior Member

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    So I found this video on YouTube regarding the brake booster pump:


    The sound I'm describing isn't quite this sound. It happens after I've turned on the car and it's louder than this brake booster pump sound for sure. Thanks for your response though!
     
    #3 Ella, Feb 23, 2018
  4. BlueCrushSteve

    BlueCrushSteve Junior Member

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    It could be the Dilithium Chrystal's powering up the Flux Capacitor.
     
    #4 BlueCrushSteve, Feb 23, 2018
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  5. Ella

    Ella Junior Member

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    This is what makes time travel possible, after all! :D
     
    #5 Ella, Feb 23, 2018
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  6. alanclarkeau

    alanclarkeau Senior Member

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    AirConditioner? Which will run if you have demist.

    Try, when you park at night, turn the Climate Control OFF (might have to reduce the temperature to the minimum to ensure the heater doesn't try to work. That way, it shouldn't try to start the Internal Combustion Engine - see what sounds occur. I've counted up to 8 different soft sounds from when I approach the car to when I start driving - each sounding like I'd imagine a Flying Saucer to make on start-up (though louder).
     
    #6 alanclarkeau, Feb 23, 2018
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  7. Ella

    Ella Junior Member

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    Great idea, I'll definitely give it a try! I have had my heater running in the winter so that may be it. I just remember being alarmed at the sound since I thought Priuses (Prii? :confused:) were supposed to be relatively quiet at start up! Thanks for your help!
     
    #7 Ella, Feb 23, 2018
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  8. RRxing

    RRxing Senior Member

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    It would help us diagnose if you can get a recording of the noise...
     
    #8 RRxing, Feb 23, 2018
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  9. bisco

    bisco cookie crumbler

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    prius are actually quite noisy at start up.aside from the engine.
     
    #9 bisco, Feb 23, 2018
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  10. kithmo

    kithmo Couch Potato

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    My money is on it being the ICE, it starts up straight away if the climate control is left on and it does sound noisier on cold start, revs higher and runs rougher for a few seconds.
     
    #10 kithmo, Feb 28, 2018
  11. RCO

    RCO Senior Member

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    Erm, mine waits for about 5-10 seconds before starting the petrol engine.
     
    #11 RCO, Mar 1, 2018
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  12. RRxing

    RRxing Senior Member

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    Did the OP ever find out what was making the noise???
     
    #12 RRxing, Mar 1, 2018
  13. kithmo

    kithmo Couch Potato

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    In other words straight away :p
    What I meant to say was it starts up sooner if the climate is left on.
     
    #13 kithmo, Mar 1, 2018
  14. Data Daedalus

    Data Daedalus Senior Member

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    Brake hydraulic booster. Even my old Gen 2 makes that noise when I open the front door first thing in the morning. It also makes a raft of similar noises after you’ve parked and disembarked from the vehicle. Strange hisses, that brake hydraulic booster probably powering down, and other one off noises that wouldn’t be out of place on a certain YT-1300 Corellian Freighter that has just touched down on a landing pad. The only thing missing is visible gases being randomly vented....


    iPad ? Pro
     
    #14 Data Daedalus, Mar 11, 2018
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