Inverter cooling water pump replaced - but have a humming sound

Discussion in 'Gen 2 Prius Technical Discussion' started by enginestarter, Sep 10, 2019.

  1. enginestarter

    enginestarter Junior Member

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    I got the POA93 some time ago...
    Finally got changed today.
    Drives well and all seems OK.
    I've only driven a few miles.

    The only thing is... I hear a light humming noise when turned on.
    It's not really a humming noise - but the closes word I could find to describe.

    I bought a pump from ebay. I'll be selling my car in 1-2 years, so wasn't worried about getting an original part.

    Any ideas about the sound?

    Thanks.
     
  2. frankv64

    frankv64 Junior Member

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    Did you bleed the system? Maybe that’s what you’re hearing


    iPhone ? Pro
     
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  3. valde3

    valde3 Senior Member

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    A working pump does make a slight noise. If the fan and engine are off you can easily hear it in the car if parked in quiet place. If fan is in slowest speed I can still just hear it. But any more noise than that and I can't.

    If your pump is noisier than that try to bleed the system. If there is no air in system and it's still too loud then it might be a bad pump.
     
  4. enginestarter

    enginestarter Junior Member

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    Cool. Thanks for the replies.
    I'll be replacing with proper fluid when I get serviced, probably next week.

    Sound isn't that bad - just a little more than it was originally.
     
  5. JC91006

    JC91006 Senior Member

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    Is it low on coolant?
     
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  6. edthefox5

    edthefox5 Senior Member

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    Proper coolant?
     
  7. Skibob

    Skibob Senior Member

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    It’s because you bought a cheap aftermarket pump. Hopefully it lasts more than a month and a half like 2 posters here recently had happen.
     
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  8. edthefox5

    edthefox5 Senior Member

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    Don't be concerned about the sound check out if its circulating properly. Open the reservoir and look inside with a flashlight the fluid should look like its boiling which is strong circulation. if its just sitting there or barely moving the pump is bad and or has air in it.
    Aftermarket pumps suck.

    Very very easy to bleed.
     
  9. pasadena_commut

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    Are you sure all the bolts holding it are tight? Especially if you replaced the base plate with it. If those two bolts are not fully tightened down it might vibrate in resonance with the normal pump frequencies which would make it a bit louder. A working pump can be felt to vibrate with a finger, and I can hear it if standing over it with the hood up, but if anything else is going (like even the ventilation fan in the car) then I can't hear it. On the other hand my hearing sucks, so others probably hear the pump when I wouldn't.
     
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