Does this sound like a failing wheel bearing?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by brick, Oct 2, 2009.

  1. brick

    brick Active Member

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    The car has just developed a new sound coming from the front end. For now it's only noticeable above 50mph or so and quite faint. The closest thing I can think of is the sound made by blowing across the top of a half-full coke bottle, or maybe a lower-pitch version of running your finger around the rim of a wine glass (if you're skilled enough for that sort of thing). The pitch definitely changes with road speed rather than engine speed. Other descriptions I have read around here range from metal-on-metal to jet engine. And the last time I had a toasted bearing on a different car it consisted of a droning hum which was a completely different sound.

    Unfortunately (I guess) the sound isn't yet distinct enough to pin it on one side or the other.
     
    #1 brick, Oct 2, 2009
  2. richard schumacher

    richard schumacher shortbus driver

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    Could be, in which case you need a dealer pronto. But first check the undersides of both side mirrors. The screw holes there should be covered by plastic tape. If they are not, try that; the sound may go away.
     
    #2 richard schumacher, Oct 2, 2009
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  3. hobbit

    hobbit Senior Member

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    I'd think a failing bearing would be much more rumbly than the
    whistle you're describing. But tire treads could also produce
    something like that, depending on their spacing. How old are
    your tires?
    .
    You probably want to at least do the top-to-bottom shake of each
    wheel and check for bearing play. Might help to go around with
    the jack and unweight each corner of the car in turn, if not
    get the wheel entirely off the ground to test.
    .
    _H*
     
    #3 hobbit, Oct 2, 2009
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  4. brick

    brick Active Member

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    Thanks, guys. The tires (hydroedge) have about 4k miles on them so they are still wearing-in and might be the culprit. I'll investigate all of the above as suggested. If the shake test doesn't reveal anything maybe I should do an early tire rotation and see if it makes a difference.
     
    #4 brick, Oct 3, 2009
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  5. brick

    brick Active Member

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    Well, I found zero play from the wheels when I jacked them up and gave a good tug. They may as well have been welded to the axles. I guess it's just the tires singing a little at high speed.
     
    #5 brick, Oct 3, 2009
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  6. richard schumacher

    richard schumacher shortbus driver

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    Ehh, that's not really an adequate test, as others here have discovered, because a person probably can't necessarily exert sufficient force. If you think there is *any* chance of a bearing problem, have a dealer check it out. Losing a wheel on the freeway can ruin your whole day.
     
    #6 richard schumacher, Oct 5, 2009
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  7. EZW1

    EZW1 Active Member

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    Tires create an incredible amount of noise. And, depending on the tread design, that noise will change amplitude and tone as your speed changes. This very well could be your issue - especially since the wheels were tight on the axles when you did your test.
     
    #7 EZW1, Oct 5, 2009
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  8. hobbit

    hobbit Senior Member

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    Like I observed a while back, after front/back swapping my
    hydroedges after a bit too long in one position I had *horrendous*
    tread noise. Partially because of different camber fore and aft,
    and partially because of the slight RR misalignment. Having
    the noise increase radically after the rotation was the big clue
    that it had nothing to do with bearings... but that was after
    a bit more than 4K in my case. In general, though, the HEs are
    on the noisy side especially at the pressures we tend to run.
    .
    Oh, and if it peaks around 18 MPH, that's another good indicator.
    That seems to be about where it all strikes resonance.
    .
    _H*
     
    #8 hobbit, Oct 5, 2009
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