What noise is this?

Discussion in 'Gen 3 Prius Main Forum' started by Tickwood, Dec 29, 2009.

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  1. Tickwood

    Tickwood Active Member

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    When I open the driver door on my 2010 after the car has been sitting for anywhere from several hours to more than 24 hours I get about 5 seconds of a low whirring sound. it is not the thermos bottle pump noise such as I heard on my 2004 as the car has completly cooled off.
    What is it? All I need to do is open the door, not lean on it or sit in it.
     
    #1 Tickwood, Dec 29, 2009
  2. F512M

    F512M Member

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    I get the same noise on my 2010 Prius V. I would also like to know what the noise is. Thanks for posting.
     
    #2 F512M, Dec 29, 2009
  3. spiderman

    spiderman wretched

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    Brake accumulator pump/motor. It is readying the brakes for action.

    Here is a good thread on why it should/should not operate with the door opening.
     
    #3 spiderman, Dec 29, 2009
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  4. qbee42

    qbee42 My other car is a boat

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    It's the brake accumulator pump. The Prius uses electrically assisted power brakes, which use an electrically driven pump for hydraulic pressure.

    The Gen III Prius has no thermos bottle.

    Tom
     
    #4 qbee42, Dec 29, 2009
  5. rrolff

    rrolff Prius Surgeon

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    Brakes pumping up (electric hydraulic system). The car works differently from standard cars with a belt to assist the brakes (when the engine is on, the brakes are assisted via pulley).
     
    #5 rrolff, Dec 29, 2009
  6. PriusLewis

    PriusLewis Management Scientist

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    You mean it's NOT the car purring with pleasure to see me back again? :( Dang! :D

    Hydraulic brake assist wouldn't work very well on a car whos engine only runs part time. Manufacturers had a tough enough time with turbo-and supercharged cars since under boost they produce no vacuum for the brake booster (these cars use a vacuum accumulator bottle and one-way valves to keep the system under negative pressure). One ton American pick-ups used to use hydraulically assisted power brakes, but that required the pump for the power steering to also power the brakes. They were fussy and a pain to work on.
     
    #6 PriusLewis, Dec 30, 2009
  7. HTMLSpinnr

    HTMLSpinnr Super Moderator
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    Been answered a few times - see linked thread.

    **Closed**
     
    #7 HTMLSpinnr, Dec 30, 2009
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