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    420benz New Member

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    Location:
    lawrenceville Ga.
    Your Vehicle Year:
    2006 Prius
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    Very hard to describe this sound but it is coming from under the hood and lasts for about 10 seconds.
  2. Offline

    SWAT Native Junior Member

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    Location:
    Atlanta
    Your Vehicle Year:
    2004 Prius
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    Is it a whirring or humming kind of sound? Mine does that, too. I figured it has something to do with the electric motor shutting down.
  3. Offline

    420benz New Member

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    Location:
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    2006 Prius
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    YES. It always had a humming sound,but it is much louder now and lasts longer.
  4. Offline

    seilerts Battery Curmudgeon

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    Location:
    Santa Fe, NM
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    2005 Prius
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    Perhaps you are referring to the sound of the pump on the coolant heat storage tank? After you shut off the car, this pump fills the thermos-like tank with hot coolant so that the engine can warm up faster and have lower emissions on the next start.
  5. Offline

    Patrick Wong DIY Enthusiast

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    Location:
    Green Valley, AZ
    Your Vehicle Year:
    2007 Prius
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    You should hear a similar sound as you are starting up the Prius for the first time in the morning.
  6. Offline

    Rae Vynn Watch out, I have a degree in BS!

    Member Since:
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    Location:
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    If you peruse the Owner's Manual, you will see several entries concerning various sounds that the Prius makes, when the engine is not running/Power is not "ON".

    All of these entries note that "this sound is perfectly normal"
  7. Offline

    JimboPalmer Tsar of all the Rushers

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    Location:
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    I have never been "perfectly normal", what's that like?
  8. Offline

    seatown7 Northwest Prius Dork

    Member Since:
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    I've heard its quite boring and tedious...;)
  9. Offline

    Rae Vynn Watch out, I have a degree in BS!

    Member Since:
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    Location:
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    "Normal" is a setting on a clothes dryer.

    For the rest of us, "Functional" suffices :thumb:
    1 people like this.
  10. Offline

    420benz New Member

    Member Since:
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    Location:
    lawrenceville Ga.
    Your Vehicle Year:
    2006 Prius
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    Thanks guys. This is a great forum.
  11. Offline

    richard schumacher shortbus driver

    Member Since:
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    It could be the sound of the coolant transfer pump failing. A failing one tends to get noisier in cold weather.
  12. Offline

    420benz New Member

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    Location:
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    2006 Prius
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    Where is it located and is it a DIY replacement?
  13. Offline

    Patrick Wong DIY Enthusiast

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    Location:
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    It is located near the coolant heat recovery system canister, in the front left wheel well in front of the tire. Replacement could be DIY if you consult techinfo.toyota.com or look up my post about how to replace engine coolant.

    However I wouldn't go to the trouble of replacing the pump just because it is noisy. If no DTC is logged by the engine ECU (which would cause the check engine light to appear), then no worries.

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