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Coolant reservoir basically empty

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by kolski, Apr 7, 2019.

  1. kolski

    kolski Junior Member

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    Hey everyone,

    I recently changed out the coolant in my 2008 prius for both the inverter and the engine. I did this because I was getting the Check Engine code P1121. I drove around for a couple of days with no check engine light, and today it came on. I looked under the hood and my inverted coolant is at full, but the reservoir for the engine coolant has nothing :O! Should I be adding coolant to the reservoir or do I need to fill it via the radiator cap? I was pretty sure that I had replaced the old coolant with the same volume. Any help is appreciated.
     
    #1 kolski, Apr 7, 2019
  2. Raytheeagle

    Raytheeagle Senior Member

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    Check the level in the radiator and fill that as needed.

    It’s hard to bleed the Gen2 engine loop, so you probably have air in there.

    Good luck and keep us posted.
     
    #2 Raytheeagle, Apr 7, 2019
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  3. kolski

    kolski Junior Member

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    Yeah.. the video I watched showed a bleed valve, but my prius didn't have it...

    So you're saying I should only add coolant via the radiator cap, and not the reservoir, correct?
     
    #3 kolski, Apr 7, 2019
  4. Raytheeagle

    Raytheeagle Senior Member

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    The reservior is an overflow so fill that to the mark. The bleed valve is under the from brace on the drivers side of the radiator. You need a small Allen key to access it but it is there.

    Good luck and keep us posted (y).
     
    #4 Raytheeagle, Apr 7, 2019
  5. kolski

    kolski Junior Member

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    I did get the allen key bleeder, but I didn't quite understand where the air was getting out.

    I'm still confused, lol, you first said to fill the radiator, and then you said fill the reservoir..
     
    #5 kolski, Apr 7, 2019
  6. Raytheeagle

    Raytheeagle Senior Member

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    The Gen2 has the thermos that takes a bit of coolant, which is closed when you are trying to fill the coolant.

    Did any coolant come out of the bleed the first time you did the bleed?
     
    #6 Raytheeagle, Apr 7, 2019
  7. kolski

    kolski Junior Member

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    no. I don't even know where it would of come out of..
     
    #7 kolski, Apr 7, 2019
  8. kolski

    kolski Junior Member

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    Could you just reiterate one last time. Should I top off my coolant by adding into the reservoir or the radiator cap? Thank you.
     
    #8 kolski, Apr 7, 2019
  9. Raytheeagle

    Raytheeagle Senior Member

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    Radiator cap;).
     
    #9 Raytheeagle, Apr 7, 2019
  10. kolski

    kolski Junior Member

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    gracias!
     
    #10 kolski, Apr 7, 2019
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  11. Patrick Wong

    Patrick Wong DIY Enthusiast

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    You should fully fill the radiator via the radiator cap; and also fill the reservoir to the FULL mark.

    Find the bleed valve on the radiator, which needs a 6 mm Allen wrench to open. Open the valve while you are filling the radiator, and close the valve when you see fluid coming out of the valve.

    If you did not run the coolant heat recovery system pump to fill up the CHRS canister, you probably have air trapped in the system there. Also, does the cabin heater produce satisfactory heat? If not or if you hear air bubbling in the heater core, then you probably have air trapped there as well.

    See my posts #22 and #42 regarding how to replace engine coolant.
    Changing engine coolant | Page 2 | PriusChat
     
    #11 Patrick Wong, Apr 7, 2019
    Last edited: Apr 7, 2019
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  12. kolski

    kolski Junior Member

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    I DID run the coolant heat recovery system pump when filling the radiator with coolant. I do not hear bubbles, and the cabin does produce heat when required.

    Thank you for your input Patrick. I'll make sure to top off the reservoir :)

    I may just need to replace that pesky coolant control valve(?), but I was hoping this would fix the issue...
     
    #12 kolski, Apr 8, 2019
  13. kolski

    kolski Junior Member

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    After draining and replenish both of my coolant reservoirs, I no longer get a Check engine light with the p1116 and p1121 codes... *knock on wood*
     
    #13 kolski, May 7, 2019
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