1. Attachments are working again! Check out this thread for more details and to report any other bugs.

Faint, High-Pitch Whine

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by IndyDoug, Feb 27, 2006.

  1. IndyDoug

    IndyDoug New Member

    Joined:
    Sep 24, 2005
    120
    0
    0
    Location:
    Indianapolis, IN
    My Prius has just over 15k miles. Recently, I notice a very faint, high-pitch whine coming from the front engine area during the first 25 minutes of starting during the mornings. Morning temps have been in the low twenties lately. I don't notice the whine in the afternoons.

    comments?
     
    #1 IndyDoug, Feb 27, 2006
  2. Frank Hudon

    Frank Hudon Senior Member

    Joined:
    Jan 11, 2004
    4,147
    18
    0
    is this a continous whine or just durning the start up phase. IE: coolant tansfer pump whine like some of us get when it's cold. Or is it the Motor/Generator whine?
     
    #2 Frank Hudon, Feb 27, 2006
  3. hobbit

    hobbit Senior Member

    Joined:
    Mar 23, 2005
    4,089
    468
    0
    Location:
    Bahstahn
    Vehicle:
    2004 Prius
    Model:
    N/A
    Several possible sources. Coolant transfer pump [10-15 seconds
    at startup]; inverter coolant pump [continuous]; throttle control
    motor [continuous, PWM-style whine]. Those are the loudest noises
    the car makes when the ICE isn't running, assuming you've got the
    a/c fan off. The inverter tends to make a soft, 10khz whine when
    under heavy loads [while driving!], and sometimes you can hear that
    through the AM radio as well.
    .
    _H*
     
    #3 hobbit, Feb 27, 2006
  4. IndyDoug

    IndyDoug New Member

    Joined:
    Sep 24, 2005
    120
    0
    0
    Location:
    Indianapolis, IN
    Yes, A/C fan is off. Noise only lasts for about 25 minutes during my morning commute.
     
    #4 IndyDoug, Feb 28, 2006
  5. hobbit

    hobbit Senior Member

    Joined:
    Mar 23, 2005
    4,089
    468
    0
    Location:
    Bahstahn
    Vehicle:
    2004 Prius
    Model:
    N/A
    wow, that long. Hmm. If you could try to localize it under the
    hood, that would help. Bad bearings in the inverter coolant pump,
    perhaps? If you stick your hand down in the hole in between and
    slightly ahead of the inverter and the relay block, you hit it;
    black plastic thing 2 inches or so across with a hose on top and
    another to the side.
    .
    _H*
     
    #5 hobbit, Mar 2, 2006
  6. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator
    Staff Member

    Joined:
    May 11, 2004
    14,816
    2,498
    66
    Location:
    Far-North Chicagoland
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Advanced
    Ohhh. I completely ignored this thread early on because when I read the title, "Faint, High-Pitched Whine" I assumed that it had something to do with American automobile manufacturers. Then it occured to me that "faint" is out of place.

    All I can think of, Doug, would be to take the car to a dealer and leave it overnight. Get there early and with a technical witness, pop the hood and start the car. Hopefully the whining will occur. My concern is that if you drive the car there the whining will subside on the way. But yeah, I agree with Hobbit, 25 minutes of whining is a long time.
     
    #6 TonyPSchaefer, Mar 2, 2006
  7. jayman

    jayman Senior Member

    Joined:
    Oct 21, 2004
    13,439
    640
    0
    Location:
    Winnipeg Manitoba
    Vehicle:
    2004 Prius
    I can barely hear the inverter coolant pump on my 2004 Prius. The thermos coolant transfer pump makes a nasty noise when cold, especially in temps colder than -30 C. In summer I barely hear it.
     
    #7 jayman, Mar 2, 2006
  8. hillcharger5

    hillcharger5 New Member

    Joined:
    Feb 28, 2010
    2
    0
    0
    Location:
    Tennessee
    Vehicle:
    2009 Prius
    Model:
    N/A
    Hobbit, thanks for the post. Your inverter description seems to be exactly what I would like to eliminate. I just hear this when driving around town and braking between 40 mph to 20 mph. This is much more noticable when listening to AM radio. Is there a reasonable way to mask this???
     
    #8 hillcharger5, Oct 27, 2010
(You must log in or sign up to post here.)