Loud Whining Noise at 30-45mph - Can't figure it out

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by jsabowabo, Jun 22, 2023.

  1. jsabowabo

    jsabowabo New Member

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    Been trying to figure out the source of a increasingly loud whining sound coming from my son's 2009 Prius. The Prius is normal, and quiet until 25mph or so then gets increasingly loud inside. The noise is difficult to describe, but almost like a wheel bearing going out, or super loud tire noise. The noise gradually subsides around 50, then is somewhat normal at 60-80. The noise sounds like it's coming from the front of the car.

    I've replaced the front and rear wheel bearings. The front wheel bearings were shot, the rears were OK. The car has newer Michelin tires on it, replaced 10K ago by me. I also replaced all three engine mounts. I also replaced the trans fluid with the correct Toyota oil.

    The sound is present if the vehicle is coasting in neutral as well. I'm starting to think I got a bad set of tires, or even the front wheel bearing(s) I put in are faulty. I compared it to my neighbors 2009 Prius and theirs is quiet like a normal car.

    Thanks in advance everyone
     
    #1 jsabowabo, Jun 22, 2023
    Tombukt2 likes this.
  2. Tombukt2

    Tombukt2 Senior Member

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    If you put it up on jack stands on the rocker panels and sit in the car and put the car in drive maybe some standing outside of the car Do you get any kind of noises then You don't have weight on the wheels I realize that but it's a start I mean unless you beat on the wheel bearings installing them or something I wouldn't think or you bought some that are extremely cheap fake junk believe it or not there are some fake good ones.
     
    #2 Tombukt2, Jun 22, 2023
  3. pasadena_commut

    pasadena_commut Senior Member

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    Rotate the tires and see if the sound moves. Bet it doesn't. In any case, it isn't a difficult test.
     
    #3 pasadena_commut, Jun 22, 2023
  4. jsabowabo

    jsabowabo New Member

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    Thank you both for the advice. I put the car up on jack stands, put it in drive and ran it up to 40 and the noise was present. It was obvious that the passenger front was the source. I put my hand on the passenger front coil spring and spun the wheel. I could feel roughness on the passenger side; nothing on the driver's side. It seems the replacement bearing (a factory Koyo hub assembly) has already failed after less then 10K miles. Bad luck. I ordered a Dorman unit from Rockauto - lifetime warranty this time. Thanks again.
     
    #4 jsabowabo, Jun 23, 2023
  5. pasadena_commut

    pasadena_commut Senior Member

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    You want a better brand than that. Timken or Beck/Arnley are good. That lifetime warranty is almost certainly against "defects in manufacturing", not wear. There is a reason Dorman is in the cheaper class in the list of bearings at RockAuto, and Timken and Beck/Arnley in the 'standard replacement" group.
     
    #5 pasadena_commut, Jun 23, 2023
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