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Whine when stationary. Gone after 3 min.

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Stormz, Jul 26, 2016.

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  1. Stormz

    Stormz Member

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    Hi all,

    My wife has said that yesterday morning (and also a couple of weeks ago), she started the car and a constant whine came from the engine area. It went a few minutes later while she was driving.

    The morning was very cold (by Western Australian standards :) ), about 3 or 4 degrees.
    It was a constant whine, not going up or down, or with gaps.
    The car was stationary, and the whine started when she started the car (that would rule out wheel bearings).
    During driving, the whine did not change whether she was turning left or right (also rules out wheel bearings).
    No vibration in the steering (also rules out wheel bearings).
    The A/C (air conditioner) was NOT on.

    I've been trawling the forums but nothing has come close to this afaik.
     
    #1 Stormz, Jul 26, 2016
  2. bisco

    bisco cookie crumbler

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    how many miles/km on her? i'm thinking inverter pump. not the buzzing from the brake accumulator, correct?
     
    #2 bisco, Jul 26, 2016
  3. Stormz

    Stormz Member

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    Hi Bisco,

    It has about 140,000km's. 2008 model. It's not a buzzing, but a constant regular whine (not too high pitched apparently), and the first she heard it was a couple of weeks ago.

    I know the buzzing is normal when you start, but I always thought it was heating the oil up :)
     
    #3 Stormz, Jul 27, 2016
  4. andrewclaus

    andrewclaus Active Member

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    You smile but you're very close. The buzzing you normally hear at cold startup and at shut down is the heat recovery system pump heating up the throttle body for a more efficient start.

    Next time the whine happens, try turning the car off then go into "IG-ON" mode--push start twice, foot off brake. If the noise continues, open the hood and see if it's the inverter pump which is just behind the left headlight.

    Or at least try to narrow down the area with the hood open, even in "Ready" mode. The ABS actuator is on the opposite side and a noise from that might be obvious.

    Neither of those is something you want to ignore.
     
    #4 andrewclaus, Jul 27, 2016
  5. Stormz

    Stormz Member

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    Thanks for that. It's not related to being cold as it's been cold on quite a few mornings, and only happened twice so far.

    What do the inverter pump and ABS actuator do please, and what happens when they fail?
     
    #5 Stormz, Jul 27, 2016
  6. bisco

    bisco cookie crumbler

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    the inverter pump, circulates coolant through the inverter. the brake actuator is a hydraulic master cylinder of sorts. you might also be hearing inverter whine, which is annoying, but harmless.
     
    #6 bisco, Jul 27, 2016
  7. Montgomery

    Montgomery Senior Member

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    I can't answer the mechanical details of the questions you have, but I will say that the Prius makes noises all the time, at different times, at different speeds, when completely stopped, when cold, when hot, when it has been sitting for awhile and even when you walk up to it with your key in your pocket. I'm not saying your noises may not be serious, but your best bet is the dealer in regards to the specifics. For me, it took awhile for me to not worry about the sounds. And, after awhile, the sounds will make sense to you as the car learns your driving habits. Just my two cents.
     
    #7 Montgomery, Jul 27, 2016
  8. dolj

    dolj Senior Member

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    Prii outside the USA do not have the heat recovery system, so that won't be it.
     
    #8 dolj, Aug 14, 2016
  9. bisco

    bisco cookie crumbler

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    any solution?
     
    #9 bisco, Aug 14, 2016
  10. Patrick Wong

    Patrick Wong DIY Enthusiast

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    The brake actuator pump makes a buzzing noise when it operates. The reason for its existence is to produce hydraulic pressure for the braking system.

    Most cars do not have such a pump as they depend upon the gasoline engine to produce a constant source of vacuum which is used by the power brake system. Since the gasoline engine in Toyota hybrids does not run constantly, an alternate approach is required.

    Regarding the whine sound, I would not be very concerned about it since it goes away after 3 minutes. However, I suggest that you check the tightness and physical condition of the serpentine drive belt.
     
    #10 Patrick Wong, Aug 14, 2016
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