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2008 Prius rumbling when letting of the gas...thoughts?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by priuslyfe, Oct 24, 2024.

  1. priuslyfe

    priuslyfe Member

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    So I thought it was the wheel-bearing getting really bad as I could hear it lightly grinding on the drivers side front wheel. So I replaced the wheel bearing and now the "rumbling" sound is still there.

    Basically, after letting off on the gas/accelerator the car rumbles and slightly vibrates.

    Actually the car rumbles at start-up as well. I've checked the oil and don't hear any knocking pistons. The sound is coming from under my feet while driving.

    btw: it isn't a stolen-catalytic converter sound either. only rumbles while engine is on though.

    AUDIO LINK: My_recording_2[1]
     
    #1 priuslyfe, Oct 24, 2024
    Last edited: Oct 24, 2024
  2. priuslyfe

    priuslyfe Member

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    Could it be that parts of the piston are in the oil pan or would that make it essentially undriveable?? There is oil in the car engine though.

     
    #2 priuslyfe, Oct 24, 2024
  3. priuslyfe

    priuslyfe Member

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    #3 priuslyfe, Oct 24, 2024
  4. priuslyfe

    priuslyfe Member

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    betting its clogged fuel injectors after watching youtube.

    to me: thanks for the help!

    will update this thread.
     
    #4 priuslyfe, Oct 24, 2024
    bisco likes this.
  5. mr_guy_mann

    mr_guy_mann Senior Member

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    The rumbling noise in your recording definitely has a "bearing quality" to it. Wheel bearings are linked to vehicle speed, the faster you go, the louder the noise gets. Depending on how bad they get, you can start hearing around 20-40, and it will howl above 60.

    If you hear this noise when the ICE starts, it isn't wheel bearing. First I would check the engine mechanical water pump or belt pulley. Those are easy enough to isolate.

    Given how "heavy" the sound is, I would suspect that there is a bad bearing in the transmission. I would use a mechanic's stethoscope to poke around the engine and trans to listen for the noise.

    Fuel injectors can affect how the engine performs - if they cause a loss of power or misfire, then the ECM should set codes and turn on the check engine light. Also, low ICE power or misfire will not cause a bearing - rumble sound. A dead misfire causes the transmission damper to slam against its internal springs - sounds like a rod knock.

    Posted via the PriusChat mobile app.
     
    #5 mr_guy_mann, Oct 25, 2024
  6. priuslyfe

    priuslyfe Member

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    so does that mean the transmission has to be replaced or can it easily fixed?

    is there a code on the OBD reader for this?
     
    #6 priuslyfe, Oct 25, 2024
    Last edited: Oct 25, 2024
  7. bisco

    bisco cookie crumbler

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    how many miles on her?
     
    #7 bisco, Oct 26, 2024
  8. priuslyfe

    priuslyfe Member

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    310K

    i am going to really look underneath the car carefully tomorrow and hopefully I'll see what the issue is. But the whole car vibrates when I let off the gas. I don't (at least hope) its not bearings in the transmission.

    thing is when I changed the wheel-bearing I looked over the parts up to the transmission pretty carefully but it is definitely something that isn't going to go away or fix itself.
     
    #8 priuslyfe, Oct 26, 2024
    bisco likes this.
  9. priuslyfe

    priuslyfe Member

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    SOLVED!!!!

    it was the motor mount that was causing all the noise. Not to mention the initial sound of the wheel bearing that needed to be replaced.

    Over the weekend, not only was there the usual loud rumbling but also the distinct "chirping" sound of rubber mounts going bad.

    Although the dogbone didn't physically look any different than the dogbone mount I took off my parts-Prius. Replacing the mount immediately silenced the vibration noise coupled with the replaced bearing....everything is great so far.

    Thanks for all the help.

     
    #9 priuslyfe, Oct 28, 2024
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