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Intermittent thrusting sound from near fuse box

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by bill02888, Jul 31, 2017.

  1. bill02888

    bill02888 Junior Member

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    I'm the original owner of my 2005 Prius. In the past year or so I've been occasionally hearing a new sound. It's fairly quiet. I mostly hear it when I come to a complete stop, either at a traffic light, or in my garage, although I've heard it while slowly backing out of my garage too. It sounds a bit like a piston (in the generic sense, not as in an actual car engine piston) moving one way then the other. 2 full cycles in about a second. Normally it only goes through 4 or 5 cycles before it stops, but the other evening when I was parking in my garage I heard it go on and on. I popped the hood. The sound seems to be coming from the area near the fuse box. I went to get my audio recorder but by the time I got back the sound had stopped. I should have just tried using my cell phone.

    Thanks,
    Bill in central MA, USA.
     
  2. bisco

    bisco cookie crumbler

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    i'm thinking brake actuator, but not sure what they sound like. how many miles on her?
     
  3. Kevin_Denver

    Kevin_Denver Active Member

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    This could very well be your brake pump recharging pressure to the system. It will make a pumping sound after braking, though sometimes it takes a little bit for the pressure difference to work its way through the system (which is why you hear it after the car has been stopped for a short time). If it's fairly quiet, you don't have any problem.
     
  4. ChapmanF

    ChapmanF Senior Member

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    So, you popped the hood to try to locate it, but you were inside the cabin at first when you noticed it?

    And it sounds like something moving back-and-forth, couple times a second, not the more whirr-like sound of the brake pump? (I assume you've heard your brake pump plenty of times, so you can tell this sound is something else?)

    You might unzip the video attachment in this thread and see if that is like the sound you are describing.

    -Chap
     
  5. Jmack111

    Jmack111 Member

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    When you turn the hot car off you hear it from the cooling pump under the driver side head light

    Posted via the PriusChat mobile app.
     
  6. bill02888

    bill02888 Junior Member

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    Coming up on 200,000 miles. It's not the usual break pump sound which I have heard thousands of times, often after using the break a few times. It's not the usual thermos pump sound which I've also heard thousands of times. The very first time I heard the sound I was stopped at a traffic light, sitting in the driver's seat. I'll check out the video shortly.
     
  7. edthefox5

    edthefox5 Senior Member

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    It's probably the ac damper door. That usually groans but sometimes it cycles endlessly.
    You can hear it if you turn off the ac. Lots of people have that.
     
  8. ChapmanF

    ChapmanF Senior Member

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    Had a chance to check out the video yet? :)

    -Chap