Whining Sound at Highway Speeds-Normal or Sound of Major Issue?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Milkman_89, May 27, 2023.

  1. Milkman_89

    Milkman_89 New Member

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    Hi All, I recently purchased a 2012 Prius with 112k miles. At highway speeds, there is a friction-like/whining sound that I believe is coming from the driver’s side engine compartment area. This is my first hybrid, so I’m not sure if the sounds is completely normal, a major issue, or something in between.

    Sound details
    · Recording of sound can be found at:
    · Occasionally intermittent (pulsing) whining/friction-like sound is noticed at highway speeds (60+ mph)
    · Sound is like a taxiing jet
    · Sound disappears when car moved to neutral (meaning not aerodynamic, tire, or suspension related)
    · Sound occurs when giving it gas/coasting, but is louder when braking or downshifting to “B”
    · Unrelated to AC being used
    · volume is less than radio at normal volume
    · Appears to come from driver’s side engine compartment area.

    Any advice on if this is normal or if you have theory on what may be the issue would be greatly appreciated! At first I thought it was “coil whine” or the inverter, but now I’m not so sure.
     
    #1 Milkman_89, May 27, 2023
  2. bisco

    bisco cookie crumbler

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    all i can hear is road noise
     
    #2 bisco, May 28, 2023
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  3. xliderider

    xliderider Senior Member

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    I also don't hear anything abnormal, maybe you are hearing inverter whine, or the "spaceship" pedestrian warning speaker/sound generator?

    All I see are your US size 10 flip-flops, or as we call them in the 50th state, slippers.

    Posted via the PriusChat mobile app.
     
    #3 xliderider, May 28, 2023
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  4. rjparker

    rjparker Tu Humilde Sirviente

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    If it is a problem it could be a rare transaxle bearing noise. Best thing to do is to let a dealer mechanic drive it who knows normal from abnormal. A Prius has almost no sound deadening.

    Nothing actually disengages in neutral although the engine will stop. The transaxle planetary gear set is always engaged. But the engine also stops when you let off the gas or are going downhill without accelerating.
     
    #4 rjparker, May 28, 2023
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