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Coolant pump check

Discussion in 'Gen 2 Prius Technical Discussion' started by bredekamp, May 17, 2008.

  1. bredekamp

    bredekamp Member

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    How can I check that my coolant storage pump is working correctly? After I switch off the car there's no sound from the engine bay. After about a minute I hear a brief sucking noise followed by a buzzing. Is that the brake vacuum pump or the heat storage pump? What does it sound like?

    In the left wheelwell there is the sound of a pump humming in IG-ON mode. There's also a pipe going into the wheelwell/bumper area that is hot and gently vibrates when I feel it. That it?
     

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    #1 bredekamp, May 17, 2008
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I believe that the engine coolant heat recovery system is a feature that is installed in North American Prius only. I've attached a couple of exploded parts diagrams; if you want to look for these parts you'll probably have to remove the fender liner beneath the front left fender (aka driver's side in North America). That pump only runs for a few seconds after the car is turned off and various logical tests have been passed.

    The buzzing sound is probably the brake pressure accumulator pump.

    The pump that you hear running when the car is IG-ON is the inverter coolant pump.
     

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    #2 Patrick Wong, May 17, 2008
  3. bredekamp

    bredekamp Member

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    Patrick wrote:" I believe that the engine coolant heat recovery system is a feature that is installed in North American Prius only."

    Can someone confirm?
     
    #3 bredekamp, May 17, 2008
  4. ken1784

    ken1784 SuperMID designer

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    Yes. The coolant heat recovery system is for the NA Prius only.

    Ken@Japan
     
    #4 ken1784, May 17, 2008
  5. bredekamp

    bredekamp Member

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    Oh!? :eek:

    but, but....why? Strict emissions laws?
     
    #5 bredekamp, May 17, 2008
  6. qbee42

    qbee42 My other car is a boat

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    Yes. Emission laws are the reason we get the coolant thermos, and why we don't get the EV button.

    Tom
     
    #6 qbee42, May 17, 2008
  7. priusuk2008

    priusuk2008 New Member

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    ...and height adjustable seats :rolleyes:
     
    #7 priusuk2008, May 17, 2008
  8. bredekamp

    bredekamp Member

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    Toyota giveth and Toyota taketh away.
     
    #8 bredekamp, May 17, 2008
  9. priusuk2008

    priusuk2008 New Member

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    Hey bredekamp, we used to live in Plumstead but left in '02. How many Prius do you know of in Cape Town, apart from yours?
     
    #9 priusuk2008, May 17, 2008
  10. bredekamp

    bredekamp Member

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    On average I see another Prius about once every two weeks. They seem to be quite rare. I drove behind one going to work last week. I know there's another one up the road, but its' a 2005. Incidentally I test drove that one when I was looking to buy, but the mileage was high and the owner wanted too much.
     
    #10 bredekamp, May 17, 2008
  11. Patrick Wong

    Patrick Wong DIY Enthusiast

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    California historically has had worse smog in major metropolitan areas (due to automobile pollution) vs. the other 49 states. For example, Los Angeles in the 60s was frequently covered by an ominous yellowish-grey smog blanket, and your eyes would hurt and water when exposed to the smog on the freeway. Therefore the US government allowed CA to establish tighter pollution regulations for automobiles.

    Several years ago the California Air Resources Board required auto manufacturers to produce zero-emissions vehicles (ZEV). However, the deadline for ZEV vehicles was subsequently postponed as electric and hydrogen fuel cell vehicles were not deemed ready for prime time. As part of that postponement, the PZEV (partial zero-emissions vehicle) category was created.

    Prius fits into an even more exclusive category of AT-PZEV (advanced technology PZEV). The coolant heat recovery system (CHRS) and the fuel tank bladder are part of the technology that qualifies Prius for that category. This also qualifies Prius for a longer hybrid system warranty in CA and other states that have adopted the CA standards (15 yr/150K miles).

    Partial zero-emissions vehicle - Wikipedia, the free encyclopedia

    The US Classic Prius did not have CHRS. Instead it had a fancy catalytic converter with a hydrocarbon absorption chamber (HCAC) that was supposed to temporarily hold excess HCs until the catalytic converter was hot enough to start working. However that system had a valve that was prone to failure. So when 2G was released, the HCAC system was discontinued in favor of CHRS.

    Having owned both the 2001 (w/o CHRS) and the 2004 (w/ CHRS), I would not say that system noticeably improves mpg.
     
    #11 Patrick Wong, May 17, 2008
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