Noise from 2007 prius engine area

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by NMJack42, Sep 8, 2021.

  1. NMJack42

    NMJack42 New Member

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    2007 Prius - 95k miles -

    I'm getting a noise from the engine bay area - only when the gas engine is running. Video below

    searching the forums - this could be - 1) Wheels/bearings 2) water pump 3) belt/tensioner or 4) other?

    anyone have an opinion on what is causing this noise?

     
  2. Frontporch

    Frontporch Member

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    I also have a 2007.

    Unless somebody knows this outright, can you verify that when you coast, and the gas motor shuts off, this noise goes away? I know at highway speeds this probably doesn't occur, but how about a little more info, like the speed at which you notice the sound. Did it just start or progressively got louder over time/months?

    Rule out the wheel bearing.. Doesn't sound like a wheel bearing and nothing to do with the gas motor. I had a noisy water pump that I replaced. Noticed that racket more at idle and my experience was it sounded like a chain clanking. The water pump sound was overwhelmed by other road noises at highway speed. Never dealt with a belt tensioner issue, but that would be RPM based, so it wouldn't be much louder on the freeway.

    It sounds to me like some kind of electric pump, but my gut tells me something tire related. If its tire related I would't just think it started unless you picked up something on your tire. That would probably make a sound regardless of speed.
     
  3. NMJack42

    NMJack42 New Member

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    Just started - i was on a highway trip, and noise started while on the highway - noise has stayed about the same since then.

    no noise when parked at idle or in "maintenance mode" (where the gas engine is forced on). Noise is first noticed once i get over 15mph ish. Noise gets louder the faster i go, but then gets quieter - probably loudest around 40-45mph.
     
  4. bisco

    bisco cookie crumbler

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    does it make the same sound in your driveway with the engine running?
     
  5. NMJack42

    NMJack42 New Member

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    no noise if the car is not moving -
     
  6. bisco

    bisco cookie crumbler

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    has to be in the tranny or axles/wheels then?

    trannies are pretty rugged though, and 95k is nothing.
     
  7. Frontporch

    Frontporch Member

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    any check engine lights?

    Maybe just for ruling out the axles/wheels, does the noise change when you change the loading on the left and right side by gently swerving to the left and right at 40 MPH?
     
    #7 Frontporch, Sep 9, 2021
    Last edited: Sep 9, 2021
  8. NMJack42

    NMJack42 New Member

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    check engine lights - P0446 - Evap system vent control circuit -

    will try the swerving tomorrow.
     
  9. NMJack42

    NMJack42 New Member

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    first i tried swerving in a parking lot at low speed - 10mph - i heard nothing.

    at a higher speed, i heard a little something at 40mph on the right side probably coming from the tire or breaks - but it was a different noise that before.
     
  10. Frontporch

    Frontporch Member

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    I am afraid I am stumped. I think you have ruled out tires and suspension, since the noise was constant. Hopefully this question will move its way back to the top and get some visibility. If you take it into service and/or find the cause, please update your post so people are made aware.
     
  11. ChapmanF

    ChapmanF Senior Member

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    If you look around for a shop that has a ChassisEar, they can probably pinpoint the sound quickly.
     
  12. NMJack42

    NMJack42 New Member

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    it was the front passenger side wheel bearing. They also replaced the ball joint. The mechanic took it for a test drive and diagnosed it quickly. After replacement, it's back to being very quiet

    thanks for the help
     
  13. Frontporch

    Frontporch Member

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    That makes sense for a highway noise. I have had two wheel bearings go bad. Both were passenger side. They both had pretty big changes to the sounds they made when shifting weight left to right to the point where they almost became silent on off ramps

    glad you got it repaired and thanks for posting the fix
     
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