Rattle on ICE kick-in (low RPM)

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by yak76, Oct 3, 2021.

  1. yak76

    yak76 New Member

    Joined:
    Oct 3, 2021
    4
    0
    0
    Location:
    new england
    Vehicle:
    2010 Prius
    Model:
    II
    My 2010 prius has started making a metallic rattle while driving, It only occurs when ICE starts or stops and goes away other times.Typically low RPM. You can hear it in the cabin. I can almost have it come on constantly when the Hybrid system indicator is past the middle bar and I keep it there.

    I crawled under today and checked the heat shields starting from the front to back. But all seemed to be firm with no screws loose or missing - nothing seemed out of place - the shield under the cat converter is held on by plastic rivet like things but that was also not that lose. While under in front I reached in to check the heat shield in the engine compartment where the exhaust joins the engine. That was also firm.

    I have about 150k on the odometer and changed the spark plugs and the inverter and engine coolant last year.

    I'm really out of ideas on what could be doing this. Any thoughts?
     
  2. JC91006

    JC91006 Senior Member

    Joined:
    Nov 10, 2013
    15,119
    7,760
    0
    Location:
    Los Angeles, CA
    Vehicle:
    2010 Prius
    Model:
    V
    Do you have a shield to protect the CAT from getting stolen? If you have one, that's what is rattling.
     
  3. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    95,365
    43,238
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    does it happen at cold start up? have you cleaned the egr circuit?
     
    Mendel Leisk likes this.
  4. Mendel Leisk

    Mendel Leisk Sand Pounder

    Joined:
    Oct 17, 2010
    46,042
    32,885
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    I think we need a third-gen-with-rattle triage questionare…
     
    bisco and dig4dirt like this.
  5. meeder

    meeder Active Member

    Joined:
    Jul 8, 2019
    224
    145
    0
    Location:
    Doesburg, The Netherlands
    Vehicle:
    Other Hybrid
    Model:
    N/A
    Can't this be the cam phaser?
     
  6. xliderider

    xliderider Senior Member

    Joined:
    Apr 19, 2012
    7,180
    2,723
    0
    Location:
    Honolulu, HI
    Vehicle:
    2011 Prius
    Model:
    Three
    Did the rattle start after some work was done on the Prius?

    I had a rattle/tapping sound that was from a bolt that I forgot to tighten on the air intake hose near the passenger side headlight. Once properly tightened down, the rattle stopped.

    Posted via the PriusChat mobile app.
     
  7. yak76

    yak76 New Member

    Joined:
    Oct 3, 2021
    4
    0
    0
    Location:
    new england
    Vehicle:
    2010 Prius
    Model:
    II
    I don’t have a theft proof shield for the cat. Also the EGR circuit has not been cleaned, although this doesn’t sound like the problem. @xliderider we had loosened that bolt while changing the bulb recently, but I tightened and rechecked, and it is not that.

    I attach a file I recorded on my phone and the noise kicks in at 6 seconds or so - sorry not the best quality

     
  8. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    95,365
    43,238
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    'the shield under the cat converter held on with plastic things is NOT THAT LOOSE'?
     
  9. yak76

    yak76 New Member

    Joined:
    Oct 3, 2021
    4
    0
    0
    Location:
    new england
    Vehicle:
    2010 Prius
    Model:
    II
    Well, I did an experiment while I was under- I tied that shield with 2 separate zip ties extending in different directions. So it stopped moving. Still got the rattle, so I ruled it out.
     
  10. tankyuong

    tankyuong Senior Member

    Joined:
    Nov 9, 2012
    1,410
    611
    0
    Location:
    Central MO
    Vehicle:
    2012 Prius c
    Model:
    II
    Sounds like the death rattle
     
  11. yak76

    yak76 New Member

    Joined:
    Oct 3, 2021
    4
    0
    0
    Location:
    new england
    Vehicle:
    2010 Prius
    Model:
    II
    For serious??!
     
  12. Mendel Leisk

    Mendel Leisk Sand Pounder

    Joined:
    Oct 17, 2010
    46,042
    32,885
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    The recording didn’t sound like hydrolock (coolant getting into cylinder due to leaking head gasket) to me, but considering the miles, I’d get on the EGR cleaning. More info in my signature.
     
Loading...