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Draning sound after car turn off

Discussion in 'Gen 2 Prius Technical Discussion' started by sliss, Jan 17, 2008.

  1. sliss

    sliss New Member

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    I test drove a 2006 Prius today and after the car was shut off there was a hydrolic high-pitched sound (which is normal) but after that there was a flushing sounds, like water going down a drain, but with a bit a sizzling noise...Is that normal? A friend of mine who owns a Prius said he has never heard that sound.

    Thanks
     
    #1 sliss, Jan 17, 2008
  2. efusco

    efusco Moderator Emeritus
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    Normal...that's a feature where the warm coolant is pumped into a thermos where it's kept hot until the next time you start the car (up to about 48 hours)...this helps reduce start up emissions and speeds time to full warm up. Cool huh!
     
    #2 efusco, Jan 17, 2008
  3. billarb

    billarb New Member

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    I've had my car for three weeks and DID NOT know this. NEAT! Yet another reason to love my little car!

    Billarb
     
    #3 billarb, Jan 17, 2008
  4. Bob64

    Bob64 Sapphire of the Blue Sky

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    I think your talking about the hissing sound of the gas tank leakage detection system (not sure what the official term is)
     
    #4 Bob64, Jan 17, 2008
  5. sliss

    sliss New Member

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    Actually, it's more like a gurgle than a hissing sound. Efusco's explanation sounds correct. Is there any Prius documentation I can read about that? I did a search and couldn't find anything.
     
    #5 sliss, Jan 17, 2008
  6. sdct50

    sdct50 New Member

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    There is a powerpoint presentation that explains this very well:

    Search google under "johns stuff toyota prius tech presentation" it should be slide 41.
     
    #6 sdct50, Nov 26, 2008
  7. David Beale

    David Beale Senior Member

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    There are also two facing pages in the owners manual dealing with the "unusual sounds" the Prius makes. It basically says "anything you hear is normal, be happy".

    They include:
    1. Coolant transfer pump at startup and shutdown. It should "purr or whir", not squeal. If it squeals the pump bearings are failing, and the pump needs to be replaced.
    2. A very high pitched squeal (most will not hear it it's so high) - it's the inverter.
    3. Sometimes the fuel vapour recovery system has to depressurize when you shut down, and sometimes the valves will make whistling or squealing noises. Some even moan. This sound comes from the area of the filler cap/fuel tank.
    4. The brake system has an electric hydraulic pump, which will run in short bursts to maintain pressure. You will hear this if you press on the brake pedal, even if the car is off.
    5. Hours after you shut down the car will test certain systems, and you will hear clicks and whirs when this happens (sorry, I don't remember which systems, because I'm old, and while I have a good memory, it has a short latency period ;) ).
     
    #7 David Beale, Nov 27, 2008
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