Aisin Water Pumps - 5% Failure Rate?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Rocky Mountain Priusman, Mar 22, 2021.

  1. Rocky Mountain Priusman

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    I found this interesting. I ordered an Aisin water pump (which is supposedly the same as the factory pump) to pre-emptively replace on my 2010 Prius with 100,000 miles. The product is described as "
    AISIN WPT-190 New OEM Water Pump Kit"

    Reading through the reviews on Amazon out of 162 reviews, 95% of them are three star or above, but 5% of them (10 reviews) are one star. All of them said the pump failed within a few weeks of install.

    So that makes me wonder, are the 5% of these people who put this pump in and have it fail shortly after receiving counterfeit product, do something wrong on the install, or are they just on the unlucky end of the product quality bell curve?

    Makes me a little hesitant to replace a working water pump with one that has a 5% chance of failure. I know 5% isnt a huge number, but I'd prefer if it was less than 1%.

    Anyone have any thoughts on why 10 people out of 160 had this pump fail shortly after install?
     
  2. ChapmanF

    ChapmanF Senior Member

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    I had a colleague suggest something to me several years ago that can get left out of the "ABC builds the frobbitz sold by XYZ" conversations a lot of the time. ABC can run the line to make a big frobbitz order to XYZ's specifications, and they can run the same line to make a bunch to sell through other channels, and they don't have to be the same. They could switch some components to cheaper sources, or they could even just dial back the QA standards on the line. They can produce the thing at lower cost either by reducing the labor cost of testing it, by reducing the number of units plucked off the line as QA rejects, or both. People commonly assume that such adjustments are hard to do, and therefore anything that comes off the same line is going to be to the same specs. But a lot of the things, like QA targets, are easy to tweak, and even keeping two supplies of a certain component might not be impractical if the cost difference times the number of units in a run is worth it.

    And those are just the possibilities for parts that really are made "by the same OEM that makes them for XYZ".

    Counterfeiting, which also happens, is a whole 'nother thing.
     
  3. Rocky Mountain Priusman

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    Interesting... so what would you do? Install the new pump pre-emptively at 100,000 miles , return it, or set it aside to wait till the original blows?
     
  4. ChapmanF

    ChapmanF Senior Member

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    Well, hmm. You have a 2010.

    One of the ways the original pumps can fail is by having the impeller break. Then it doesn't really pump water, but the motor spins extra fast, and a 2010 won't report that as a problem (it only has a trouble code for too-slow). The trouble code for too-fast was added in 2011.

    Do you have something like a ScanGauge set up that shows you the coolant temps in normal driving? Do you glance at it from time to time?

    If so, you might just want to wait, since you've given yourself a way to notice a problem quickly if the current pump breaks its impeller and the car doesn't notice it spinning too fast.

    On the other hand, if you don't have a day-to-day coolant temp display or you're not in the habit of looking at it, and you're driving a 2010, maybe you would weigh more heavily the option of replacing preemptively.

    If you had a 2011 or later, knowing it could alert you to too-fast as well as too-slow problems, maybe you'd be comfortable waiting, and letting the car tell you when there's a problem. (Only, hmm, I don't remember if the too-fast code lights the check-engine light.)

    Anyway, those are examples of the kind of things you might weigh in making the preemptive-replacement decision.
     
  5. Andy H.

    Andy H. Junior Member

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    I ordered a aisin water pump from rockauto and received it the other day. LOOKS IDENTICAL. However its looks like someone thought it was a weapon and ground on it. After comparing New vs old it seems Toyota or other manufacturer name was ground.

    SM-N960U ?
     
  6. AzusaPrius

    AzusaPrius Active Member

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  7. ChapmanF

    ChapmanF Senior Member

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    I wonder how they pick which ones they will grind Toyota off of and sell through other channels?
     
  8. ASRDogman

    ASRDogman Senior Member

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    Why not just change the Electric Water Pump magnet?
    The impeller is what brakes, right?


    You can go to the time 5:45 to see how to take it out:


    About $50... Impeller.jpg
     
    #8 ASRDogman, Mar 22, 2021
    Last edited: Mar 22, 2021
    Georgina Rudkus likes this.
  9. Rocky Mountain Priusman

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    I should mention that my 5% figure is probably wrong. I am guessing that 9/10 people who had the pump fail left a one star review. Probably only 5/10 people (or less) who had the pump work left a good review.
     
  10. Grit

    Grit Senior Member

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    it would be like counting the number of registered pc members on the forum and divide by the members who reported with burning oil issues. Then use the output value as percentage of prius burning oil when not everyone in the world that owns a prius is a register member of this forum, or came here & reported oil burning issue.
     
  11. SFO

    SFO Senior Member

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    Was there a link for this $50 replacement magnet? (didn't watch either video)
     
  12. ASRDogman

    ASRDogman Senior Member

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    You can find them on ebay...
     
  13. Tekken

    Tekken Member

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    10 out of 160 people had detailed what fail on their pump? Pump magnet or Motor fail ?

    The majority of prius water pump fail didn't have high % indication on Pump magnet or impeller broken. By changing just the Pump magnet / pump impeller still a high risk.

    Also, Doesn't Lexus using same water pump model as prius? Are they having water pump fail issues?
     
  14. ASRDogman

    ASRDogman Senior Member

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    I guess no one really know why they fail? Since the impeller assembly is what's rotating, it seems
    that is what would fail, and does, most of the time.
    Perhaps just that part, and seat, would be a preventive maintenence thing.

     
  15. Tekken

    Tekken Member

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    That's true... so far google search showing magnetic rotor / impeller broken that's what cause water pump fail most. Are there any code indicate out if motor or electronic fail inside of pump ?

    That's only $70 save if we just change the magnet rotor + impeller. the pump is $120 and $30 for coolant = $150 if self labored.
     
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