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Inverter coolant pump questions

Discussion in 'Gen 2 Prius Main Forum' started by w2co, Mar 2, 2012.

  1. w2co

    w2co Member

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    A while back the dealer replaced the inv. coolant pump in my 06 prius a while back, and it sure doesn't have the same flow the old one had. When I asked about it the mechanic argued that it has multiple speeds and this is why I was seeing only low flow, and when it gets hot it should go faster. Now I have, after driving on the highway, pulled over and saw/heard only the same low flow in the reservoir. I have bled the system twice more and only once did I get an air bubble so i think it's good.
    BTW -This is the same dealer who consistently over fills the engine oil by .5qt every time, and I had to drain some afterwards. Now I do all my own maintenance, but the question is: has anyone else had this experience with inv. coolant pump? and is this normal operation for the "newer replacement pump"??? Thanks in advance for any info on this issue. :confused:
     
    #1 w2co, Mar 2, 2012
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    The inverter coolant pump runs at one speed whenever the Prius is IG-ON or READY. If you look at the wiring diagram you will see that the hybrid control ECU controls the water pump relay but there is no provision to pulse width modulate the motor current, or in any other way adjust the motor speed.

    I replaced the inverter coolant pump on my 2004, and then had the pump on the 2007 replaced after the LSC was announced. In both cases I did not notice a difference in coolant flow per visual observation of fluid turbulence in the reservoir.
     
    #2 Patrick Wong, Mar 2, 2012
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  3. w2co

    w2co Member

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    Thanks Patrick, well I know it had more turbulent flow before the pump was replaced. This was around 6 mos. ago but the car runs fine. I haven't driven it very far since however, so it hasn't really ever gotten very hot at all. There is flow but just not as much now. pump is quiet which is another sign it is running correctly and with no air in the system. I may take it on a road trip and am a little worried about this..
     
    #3 w2co, Mar 2, 2012
  4. w2co

    w2co Member

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    And yes I realise it only has one speed so that mech. was full of it.
     
    #4 w2co, Mar 2, 2012
  5. hill

    hill High Fiber Member

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    It's always a horrible experience when the so called Toyota hybrid "master mechanic" blows smoke up you. We just took our hybrid in today, for an Inverter coolant service bulletin. Their inverters are running hot. At least the RX and hihy SUV's are. Then there's a tsb for our crankshaft pulley. And of course the dreaded Unintended Sudden Acceleration 'cure'. Got that all done (plus alignment last week end). When I got home from the last alignment (the 3rd of 4), about 9 months ago, I discovered the right side tire pressures had been dropped almost TWENTY POUNDS lower then the left side. Why did I take 9 month to return?
    For 1, the tires were already wasted
    for 2, I needed that long to assure I wouldn't strangle any of them. :p

    I've had them tell me running higher tire pressures will make the tires go bald in the center of the tread pattern too. I whip out pic's of our hydroedges with over 90k on them, with EXCELENT tread depth still.

    .
     
    #5 hill, Mar 6, 2012
  6. w2co

    w2co Member

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    Yes the dealer never ceases to amaze me. Last week I found coolant leakage around the ice water pump pulley and brought it in for an estimate. They said yes the water pump is bad and needs to be replaced, and they suggested replacing the belt as well. The total was around $480, the belt was around $45 alone. Upon doing a little research I found a water pump for $38 on eBay, and the belt should last for at least 200Kmiles. Geeze what a case of highway robbery. imho
     
    #6 w2co, Mar 22, 2012
  7. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I would say you are optimistic regarding the serpentine belt life. Especially if you are already going to replace the engine coolant pump, it makes good sense to replace the belt at that time as a preventive maintenance measure.

    If your car has more than 50K miles on the odometer, I am sure you will find many small cracks on the belt's interior; while the exterior of the belt is probably getting glossy due to slippage.

    IIRC the price of the belt is <$20 at Champion Toyota, Houston via weborder.
     
    #7 Patrick Wong, Mar 23, 2012
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  8. w2co

    w2co Member

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    Yes it seems a bit high estimate for a belt, although the dealer in the N. Colorado area (Stapp Toyota) has always been steep on prices. Guess they have to pay for their new huge building. The 06 has just under 30K now and has had absolutely no serious problems other than 12v battery died once and the chs pump occasionally makes the squeaking noise. The hv pack is strong too. I told them about the chs pump back when warranty was still in effect but they never did anything about it and went silent. Always gets 52-54mpg in most conditions so it's a keeper. I'll do the work.
     
    #8 w2co, Mar 25, 2012
  9. James2005

    James2005 Junior Member

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    Not trying to jack your threat, but is the dealer supposed to replace the Inverter Coolant Pump under the TSB? The salesman at the dealership where I purchased my car said they wouldn't replace it since it was no longer under the manufacturers warranty. Should I press the issue? There is no record of this being replaced on my specific car and I understand that when this part goes up it can leave you stranded.

    One a side note. My brother-in-law who also owns a Prius was sent a letter from Toyota stating that this was a recall item and the local dealership replaced it for free. His car was purchased used just like mine and his car is well beyond the manufacturers warranty (140K)

    Thanks for your help!

    James
     
    #9 James2005, Apr 2, 2012
  10. seilerts

    seilerts Battery Curmudgeon

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    James, there is a recall campaign on the inverter pump. SSC A0N.

    For those wondering about flow rate, the flow appears subdued/weak if the coolant reservoir is very full. Turkey baste out a cups-worth and see if there is a difference in the perceived flow rate.
     
    #10 seilerts, Apr 2, 2012
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