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Odd knocking noise with car stopped at light?

Discussion in 'Gen 2 Prius Main Forum' started by JT-KGY, Jun 2, 2008.

  1. JT-KGY

    JT-KGY Junior Member

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    Heard some knocking noise while with car stopped waiting at the light.
    I believe the engine also stopped at the time. This is new 08 with just
    5000 miles... heard of the noise before...

    Anyone know what the noise might be from?

    Thanks,
     
  2. pdhenry

    pdhenry It's HEEERE!

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    Sometimes the engine shudders when it stops. The engine stopping at a light is normal. The shudder is apparently a function of how warm the engine is, but I noticed it when I rented a Prius for the weekend as a sort of extended test drive. Is that what you hears/felt?
     
  3. JT-KGY

    JT-KGY Junior Member

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    Not shudder.. I didnt feel any vibration... just odd strange knocking noise...
    And since the engine already stopped, I dont think it's from the engine..strange...
     
  4. Mr Kermet

    Mr Kermet New Member

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    Dude read your manual...
     
  5. JT-KGY

    JT-KGY Junior Member

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    It's in the manual? I searched a bit on the forum too.. didnt find anything.
     
  6. ZC1

    ZC1 Junior Prius Owner

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    So did you finally roll down your window and give the officer your license?

    ZC1
     
  7. JT-KGY

    JT-KGY Junior Member

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    What?? :confused:
    What does that have to do with the noise?
     
  8. ZC1

    ZC1 Junior Prius Owner

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    Odd knocking noise with car stopped at light? Right?

    I have same year car and it's all I could think of.

    (forget it, lost humour)

    ZC1
     
  9. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Perhaps you are hearing the sound of the brake pressure accumulator pump? When the car is READY, repeatedly depress the brake pedal until you hear the pump run.

    If this is the same noise that you described above, then you have your answer. If a different noise, then I have no idea what it might be - unless a bird landed on your hatch and was tapping on the glass with its beak.
     
  10. morpheusx

    morpheusx Professor Chaos

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    is it loud? I haven't ever experienced this in a Prius, but in a different car I once had alot of pressure in the fuel tank that made a tapping noise. I loosened up the gas cap and it depressurized and quit making the noise.