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Water Pump Question

Discussion in 'Gen 3 Prius Main Forum' started by MelonPrius, Jul 3, 2024 at 7:55 PM.

  1. MelonPrius

    MelonPrius Senior Member

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    I know this topic has been covered before, but I'd still like to get some feedback.

    At 120k miles, I'm going to replace my water pump out of precaution. There are no obvious signs of needing replacement. But I'll be taking a few trips this summer driving through long stretches of desert.

    1. Can I just replace the engine water pump, or is it common practice to replace both water pumps?

    2. While the mechanic is doing the work, is there anything else that needs to be done? I read in another thread that the thermostat should be replaced but I'm not sure how many miles they last.

    3. Does it matter which brand of water pump to use? What is recommended.

    I had my EGR cleaned at 90k miles. I'll need a new hybrid battery within a year (38% life left as per Dr. Prius) and don't know if I'll get a new battery or sell the Prius. So, I'm not looking to spend too much money just in case I end up selling the car soon.
     
    #1 MelonPrius, Jul 3, 2024 at 7:55 PM
  2. bisco

    bisco cookie crumbler

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    i don't think we've seen enough water pump failures at your age and miles to bother
     
    #2 bisco, Jul 3, 2024 at 8:01 PM
  3. PriusCamper

    PriusCamper Senior Member

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    With the quality issues with pumps these days you may be trading in your original water pump that's more reliable for another pump that less reliable.

    And because these water pumps are easy to replace if they fail... Just buy a spare pump and watch a you tube video on how to replace it and wait for an error code telling you the pump is bad before replacing it.
     
    #3 PriusCamper, Jul 3, 2024 at 8:13 PM
  4. JC91006

    JC91006 Senior Member

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    If you're thinking of possibly selling the Prius, I wouldn't bother changing out the pump. Mine had an error code at 214k miles. It was a over rotation code, it didn't actually fail. I went on Amazon and bought a new water pump rotor to replace the old unit. Yours at 120k miles should have plenty of life left (at least another 50k before you need to think about replacing it)

    I didn't want to spend a lot on this engine as it's nearing the dreaded "need head gasket" mileage. So I refurbished the water pump with a new rotor and it should last until the engine needs a head gasket.
     
    #4 JC91006, Jul 3, 2024 at 11:26 PM
  5. ChapmanF

    ChapmanF Senior Member

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    There has to be an explanation for the overrevving though. Often it happens when a part of the pump impeller has broken off so that it can spin faster because it's moving less water.

    Another cause can be coolant so low it is spinning in air, which is also not ok.

    It seems like Toyota added the P148F overrevving code in 2011; a 2010's water pump can have its impeller break like that and you don't get a code, because its ECM was never programmed to think spinning too fast could be a problem.
     
    #5 ChapmanF, Jul 4, 2024 at 11:28 AM
    PriusCamper likes this.
  6. JC91006

    JC91006 Senior Member

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    I did check the impeller fins and they were not broken. The thing I did notice was the thin plastic magnetic housing on the rotor was broken and somehow that made the impeller spin at an irregular speed.

    The error that came up was simply the temperature symbol on my dash. It came up for about 10 seconds and it went off. That's the only indicator of the actual error, the car was driving normally. P148F came up and the rotation was about 800rpm faster than normal

    My coolant was slightly low, maybe had to add 8oz a few months ago. I was worried that was a sign of head gasket failure but after adding the 8oz, the coolant has been stable.
     
    #6 JC91006, Jul 4, 2024 at 12:50 PM
    Last edited: Jul 4, 2024 at 1:43 PM
  7. PriusCamper

    PriusCamper Senior Member

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    Good example of growing pains for new technology... It's probably better than the older water pump tech, but at first it doesn't seem like it.
     
    #7 PriusCamper, Jul 4, 2024 at 2:13 PM
  8. MelonPrius

    MelonPrius Senior Member

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    Thanks for the input, everyone. Based on the feedback, I'll hold off on the water pump for now. I had a '96 Jaguar and I was on my 3rd water pump before hitting 110k miles. I love the Toyota dependability on certain parts.


    Thanks for the response. Just out of curiosity, what is your "need head gasket" mileage? (assuming it applies to my turd gen)
     
    #8 MelonPrius, Jul 4, 2024 at 4:11 PM
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