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Please Help, Noise Behind Dash!

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Darla, May 12, 2018.

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  1. Darla

    Darla Junior Member

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    2007 Prius:
    I've started noticing this noise a couple of weeks ago. The best way to describe it is that it sounds similar to a CD player trying to play a blank CD over and over again. I hear this whether the car is in use or not as you can see in the video I have attached. In the video, I turned off my car AC, put the car in park, No CD in my player.



    It's intermittent, but happens more than not, and much more frequently as of late.
    I know you all are the true experts. Has anyone experienced this before? Please help!
    Any response is much appreciated!
     
    #1 Darla, May 12, 2018
  2. bisco

    bisco cookie crumbler

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    welcome!

    not positive, but it might be an air direction vent flap trying to get un stuck.
     
    #2 bisco, May 13, 2018
  3. JC91006

    JC91006 Senior Member

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    That sound is from a failing 3 way coolant valve. If you change that, the sound will go away
     
    #3 JC91006, May 13, 2018
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  4. Darla

    Darla Junior Member

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    JC91006, Thank you so much!
    Are you certain of this? I have not had any check engine lights, and the car seems to be running efficiently.
    What are the other signs that the 3 way coolant valve is going bad, other than the sound? And are there any visible signs to look for before I decide to replace? Also, do you know how much this costs to replace if I took it into Toyota?
     
    #4 Darla, May 14, 2018
  5. JC91006

    JC91006 Senior Member

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    100% sure. $500 at the dealer. Parts price around $75

    When it fails, your check engine light will turn on. But your car won't break down, it'll drive like normal.
     
    #5 JC91006, May 14, 2018
  6. Darla

    Darla Junior Member

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    Thanks so much! It makes sense because my car seems to running normally, yet the sound is alarming enough to where I’ve been hesitant to drive it in long distances. I’ll probably try to replace it myself. I’ll definitely post back afterward to let everyone know, since I’m sure others might experience this.
     
    #6 Darla, May 14, 2018
  7. ChapmanF

    ChapmanF Senior Member

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    I can't hear your audio well enough to be 100% sure of anything. Another possibility you may want to explore (bisco also touched on it) is motion of one of the HVAC dampers. I've written up that issue here, and that post includes a video upload (i.e. I didn't put it on youtube, just uploaded it with the post, you can download and play it) where you can hear that sound, and also see what it will look like if you stick your head under the dash and look.

    If that's what you're getting, you can fix it in about 10 minutes with a swab and some contact cleaner, which beats $500 and even $75.

    For the record, when that happens, it isn't a damper "trying to get un stuck", but rather the HVAC computer trying to keep the damper in (what it thinks is) the "same" position, while the sensor reporting what the position is keeps jumping around.

    -Chap
     
    #7 ChapmanF, May 14, 2018
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  8. Darla

    Darla Junior Member

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    Well that would definitely be much better if that were the issue. I'm sorry about the audio. If you have a pair of headphones, you should be able to hear the sound much more clearly. I've reached out to bisco to see if he can check out my video to compare the sound. Thank you!
     
    #8 Darla, May 14, 2018
  9. JC91006

    JC91006 Senior Member

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    Next time you hear this sound, you can pop open your hood and give a good listen. It'll be much louder in the engine compartment.
     
    #9 JC91006, May 14, 2018
  10. ChapmanF

    ChapmanF Senior Member

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    And if it is louder out there, that'll confirm it's JC's thing and not my thing. :)

    -Chap
     
    #10 ChapmanF, May 14, 2018
  11. Eric D.

    Eric D. Junior Member

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    Apologies for dredging up an old thread. Got the exact same sound as in the video on an '09 with ~75k. It's audible when the engine has shut off at a stop.

    Unless there's another HVAC damper located far from the one heard when switching between fresh/recirculated air, I suspect the 3-way coolant valve. I'll listen with the hood open to make sure.

    Since there haven't been any error lights on and the car has no issues, should I be proactive in replacing the valve, or is it okay to wait until when/if a code is set?
     
    #11 Eric D., Sep 12, 2019
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