Fluttering noise when braking at highway speeds

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Anno95, Aug 19, 2021.

  1. Anno95

    Anno95 New Member

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    Hi everyone,

    I bought a 2010 Prius with 80K miles on it in 2018. It's my favorite car and drives well, but since around mid-2019 I've noticed a fluttering noise that kicks in when applying more than light force on the brakes at around 50-70 mph (noise increases proportional to speed and how hard I step on the brakes). Starting mid-2020 the noise also sometimes occurs when moving at very high speed (80 mph give or take) without braking.

    The sound seems to come from the front on the driver's side; if its minor the passenger struggles to hear it (my wife thought I was crazy at first). It feels like a heavy fan rotating or such, and seems to be unrelated to steering, thankfully. The car is now at 145,000 miles.

    Recently I got it checked at the local Toyota dealership, who said they couldn't pinpoint the cause of the noise but did notice worn rear wheel bearings, old spark plugs, and overdue fluid changes, hybrid system maintenance, and throttle cleaning. I had most of the work done elsewhere, then went back to the dealership who did the hybrid maintenance. The fluttering sound seems a bit lessened, but still shows up, especially when braking hard.

    Any thoughts on what could be causing the noise/how to get rid of it? I'm willing to put in some DIY work if feasible, but I have a pretty busy day job so I'd probably have to take it to a pro if it gets too involved.

    EDIT:
    A year ago I got a check engine light which turned out to be a dirty EGR valve, but it went away in the fall. Both the dealership and the other shop said I could ignore it, but from some reading around here it seems that cleaning might be necessary after all?
     
    #1 Anno95, Aug 19, 2021
    Last edited: Aug 19, 2021
  2. rjparker

    rjparker Senior Member

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    Did you get the wheel bearing changed?
     
  3. bisco

    bisco cookie crumbler

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    are all the aero covers fastened down solidly?
     
  4. tankyuong

    tankyuong Senior Member

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    Egr is probably the most important now
     
    Mendel Leisk likes this.
  5. Mendel Leisk

    Mendel Leisk Sand Pounder

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    You bought the car in 2018 with 80K miles. How many miles on it now?

    EGR carbon-clogging does not "go away", and left unchecked has been rumoured to lead to head gasket failure. For more info see link in my signature.
     
    #5 Mendel Leisk, Aug 20, 2021
    Last edited: Aug 20, 2021
  6. dig4dirt

    dig4dirt MoonGlow

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    @Anno95

    wOw your post has a lot of questions to it.
    But main one is, what hybrid service did the dealer do? you have a list or record of it?....just curious.
    Good on you to go elsewhere for normal maintenance. Dealers are not the greatest for that.

    Folks can tell ya 'bout the EGR mmhmmm. Not something to fahgeddabout.

    But the noise? Had the same thing in my 2015 that I just got rid of.
    Never pursued it, but yeah check the wheel bearings, that is what I always thought it was.
     
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