Water pump received with a rattle

Discussion in 'Gen 3 Prius Main Forum' started by Bob the occasional mech, Aug 17, 2025 at 5:30 PM.

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  1. Bob the occasional mech

    Bob the occasional mech New Member

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    A diagnostic scanner shows the main water pump on my wife's 2010 Prius went bad (code P261B). I ordered a new AISIN WPT-190 replacement pump online. When the new pump arrived, it was poorly packaged and the box was a little beat up looking. The pump looks ok out-of-the-box, and the impeller spins freely, but I notice it has a rattle sound. The rattle does not sound like a piece that's completely loose and flying around freely inside the pump housing. Rather, it sounds like a metal piece sliding back and forth along the impeller shaft. I suppose that sound could be normal, but I need to know for sure before I install it. What do you think?
     
    #1 Bob the occasional mech, Aug 17, 2025 at 5:30 PM
  2. Bob the occasional mech

    Bob the occasional mech New Member

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    Right after posting my question, I found the answer, although I'm a little embarrassed... The noise is coming from a metal washer at the end of the impeller shaft that is allowed to slide back and forth about a quarter inch or so.
     
    #2 Bob the occasional mech, Aug 17, 2025 at 5:40 PM
  3. Tombukt2

    Tombukt2 Senior Member

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    Yes and built-in slop once it's buried in water it'll all be otay. Lotta parts out of boxes might do similar . Product in the world that's assembled can't have zero tolerance no clearences etc . I think they found out early on that wouldn't be a good way to do it. engineer the play into the design rather than bed in upon running etc . Choices I guess .
     
    #3 Tombukt2, Aug 18, 2025 at 6:19 AM
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