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Rattling sound when accelerating

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by ag_abhishekgupta, Sep 3, 2017.

  1. ag_abhishekgupta

    ag_abhishekgupta Junior Member

    Joined:
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    Location:
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    Vehicle:
    2010 Prius
    Model:
    IV

    I'm hearing a rattling sound when accelerating up a hill or from a stop.
    The rattle or engine knocking is only happening when the hybrid system indicator shows power in the red zone. To be specific when the acceleration level is at P letter of PWR. Any lower or higher and the noise goes away.
    Please see attached video.


    Car has ~52000 miles and has been well maintained.

    I've looked under the hood and did not find anything loose. Beginning to wonder if the rattle is coming from the engine.

    Any idea what this is? I'm taking the car to dealer this Saturday.

    Thank you.
     
    #1 ag_abhishekgupta, Sep 3, 2017
  2. NutzAboutBolts

    NutzAboutBolts Senior Member

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    Can you put the vehicle in power mode and test if the noises is constant during the low and high range. Sounds like a muffler rattle but not too sure...

    Can you also rev the engine in power mode while idle in the low and high range and see if the noise is there.

    You can also have the vehicle idle and rev the engine in power mode with the hood open and have someone listen if it's coming from the engine or not.
     
    #2 NutzAboutBolts, Sep 3, 2017
  3. ag_abhishekgupta

    ag_abhishekgupta Junior Member

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    IV
    I placed the vehicle in Power mode - noise is still there at P level power - anything lower or higher the noise goes away. One additional thing I noticed is that I can reproduce the noise when the vehicle speed is low ~16 mph and power level is at P. When the vehicle is at ~40 mph, even if power level is at P (or lower/higher), there is no noise. I cannot reproduce the noise with vehicle parked and I rev the engine in power mode to different power levels.
     
    #3 ag_abhishekgupta, Sep 5, 2017
  4. NutzAboutBolts

    NutzAboutBolts Senior Member

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    Sounds like something is loose somewhere... could be from the engine or from the bottom. mayne you can try shaking your vehicle and see if you can hear it...
     
    #4 NutzAboutBolts, Sep 5, 2017
  5. ag_abhishekgupta

    ag_abhishekgupta Junior Member

    Joined:
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    2010 Prius
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    IV
    Another observation I made today ... the noise was there on the way to work ~8am. On returning home ~5pm, I could not reproduce it. Only difference I can think of is car was in the sun with outside temp ~80F (vs ~65F in the morning). I drive about 10 miles to work. This is driving me nuts.
     
    #5 ag_abhishekgupta, Sep 5, 2017
  6. NutzAboutBolts

    NutzAboutBolts Senior Member

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    well, somethings not tighten up somewhere that is causing the rattle. Probably something is hanging on to dear life lol...
     
    #6 NutzAboutBolts, Sep 5, 2017
  7. Aaron Vitolins

    Aaron Vitolins Senior Member

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    My Prius v has been making a very similar noise. Sounds like something is loose in the exhaust or manifold area. When I replaced my spark plugs I got under the car, look over the top/back of the engine, couldn't find anything! If you ever find out please let me know
     
    #7 Aaron Vitolins, Sep 5, 2017
  8. Grit

    Grit Senior Member

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    Location:
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    Vehicle:
    2012 Prius
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    Before I bought my prius, I test drove one at Hanless Davis, CA. When I got up to speeds of 35 mph, there was a random rattle underneath the vehicle, coming from the bottom of left rea/r passenger side. It stopped as I got to speed of 50 mph so that was weird, and walked away from the vehicle. The first thing I thought of doing if this ca/r was serious for me to buy was to undo the prius' underside plastic covers and see if a rock was up there going back and forth. So I pulled over and banged the cover where the sound was coming from and it was a rock as I suspected. It must have made its way in up into the covering.

    Check and locate the vicinity of the rattling and unclip the cover and see if a rock is there and then throw it far/ as possible, hope thats the issue and not anything costly to be replace/repaired.
     
    #8 Grit, Sep 5, 2017
  9. ag_abhishekgupta

    ag_abhishekgupta Junior Member

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    #9 ag_abhishekgupta, Oct 29, 2017
    ChrisFaehrtPrius, Thomaus, Raytheeagle and 1 other person like this.
  10. NutzAboutBolts

    NutzAboutBolts Senior Member

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    I hope you got that heat shield replaced with a new one lol. That’s one rusted heat shield. Glad you fixed the issue.
     
    #10 NutzAboutBolts, Oct 29, 2017
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