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Coolant & Valve Replacement Questions

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by HiccaBurp, Sep 26, 2018.

  1. HiccaBurp

    HiccaBurp Junior Member

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    I have a 2007 with 235k miles i've owned since new. Have a few coolant questions. I've read a couple of threads, especially the long one, and it's information overload.. lol

    1. It threw a code a while back for the coolant valve assy. 16670-21010 pic below. This is part of the ICE cooling loop, correct? Or inverter?

    2. The inverter coolant has never been changed. I am changing it. Any tips or tricks would be great. I do have an "air lift" to help with the process if needed.

    3. The ICE coolant was changed when the water pump was replaced around 100k miles. I am changing the coolant. I do have an "air lift" to help with the process if needed.

    4. I might as well do both since i'll be playing with antifreeze.. one and done. Anything I should know? Should I put the car in "test mode" or whatever it's called to keep it running once the coolant has been changed?

    Thanks for any help!

    [​IMG]
     
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  2. JC91006

    JC91006 Senior Member

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    1. Ice coolant loop
    2. Just drain and fill, no real need to bleed it. Check the fluid level and top off as needed until level stable.
    3. 100k - 235k = way overdue
    4. With an airlift, you probably don't have to do much as there shouldn't be any air in there. But you can always run your heater at high speed and make sure the heat works and the coolant is circulating properly.
     
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  3. exstudent

    exstudent Senior Member

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    Use the AirLift, makes life EASY.

    In theory there is supposed to be no air in the system b/c of the vaccuum created by the device. However, I have noticed that there must be some minimal amount of air that gets left behind, b/c the Engine Loop has to get topped off w/ a few ounces at the radiator, after a few days of driving.

    Geez, original owner, and NEVER changed the Inverter coolant loop. Did you not look at the maintenance schedule? Good thing you didn't have any warranty issues involving the Inverter loop, b/c you would likely get denied for lack of required maintenance.
     
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  4. HiccaBurp

    HiccaBurp Junior Member

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    Thanks JC!
    For the inverter loop, just drain and refill? There is a bleeder to help get the air out, i saw some people attached a hose and routed it back to the reservoir?

    For ICE coolant loop. I read there is a drain at the radiator and there is one in the back of the engine? I imagine I would drain as much coolant as possible, replace the coolant control valve, then add new coolant and use the air lift to help the process?

    And yes, way overdue for the coolant replacing. I've done the transaxle twice. I've done the spark plugs and pcv valve twice. Not sure why i never did the coolant :( Also, never bled the brakes either :(

    Ok, never used the air lift, but watched a video on it. Seems easy enough?

    I can't believe I waited this long to change it. Hopefully everything is ok and i'll give her more love moving forward.

    Thanks for all the help!
     
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  5. exstudent

    exstudent Senior Member

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    Once you use an AirLift, you'll never refill the cumbersome traditional way. FAST and elimination of air gaps upon refilling is why shops use it.

    However, I notice there has to be some residual air that remains in engine loop due to need to top off radiator directly. Inverter loop no issues whatsoever.

    Be sure to check the radiator after car has sat overnight. I thought 6hours later was enough time to cool and loose pressure. Nope, there was still some preasure, despite the time and everything cool to barely warm to the touch.

    Airift must have plenty of coolant when refillong. Do not let the tool sucks in air; defeats the tools purpose.
     
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  6. HiccaBurp

    HiccaBurp Junior Member

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    Thanks exstudent. Question.. how many gallons should i have to complete both, the ICE and Inverter Coolant Loops?
     
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  7. exstudent

    exstudent Senior Member

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    Engine loop = 2gal (Toyota manual lists 9.1 quarts)
    Inverter loop = 1gal (can't find spec)

    I have done engine and Inverter twice, and used the 3gal total, w/ a little bit remaining; even after filling the respective opaque overflow reservoir. You will likely have the same experience. DON'T SPILL.
     
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  8. HiccaBurp

    HiccaBurp Junior Member

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    Thank you!