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2005 Prius not bleeding after Inverter Coolant change.

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by AndyFromWI, Aug 11, 2024.

  1. AndyFromWI

    AndyFromWI Junior Member

    Joined:
    Aug 8, 2018
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    Location:
    Cumberland, WI
    Vehicle:
    2009 Prius
    Model:
    N/A
    8/11/2024: Solved! See below.

    I just drained and replaced the coolant in a 2005 Prius.
    Jack up car, Removed 24mm Inverter Coolant drain plug.
    Lowered car, removed Inverter Reservoir cap, lowered car, let it drain, jacked up drained a bit more, installed plug torqued to 29ft lbs.

    Drained a bit more than 1/2 gal.
    Opened bleeder valve attached clear hose, slowly filled Reservoir with at least 1/2 gal or a bit more, I did see fluid come up the plastic hose at the bleeder.

    Filled to full on the Reservoir, pressed the Start button twice (foot of the brake)
    I can hear the invertor motor run, coolant is not coming up the blead valve hose.
    Looking at the Reservoir, I'm not seeing bubbles...
    Started the engine same thing, not seeing bubbles.
    Removed the bleed valve cleaned the small hole and blew compressed air through it.
    If I keep the bleed valve off, a tiny bit of fluid does overflow, no air bubbles.

    Note: No error codes or error indications on the dashboard.

    My concern is that the inverter pump motor is turning but not moving fluid.
    I had preventively replaced the inverter pump with Toyota OEM in 2018, @ 186K miles, currently I have 248K on the Prius.

    I did try squeezing some of the hoses and could hear the sound of the inverter pump changing, it helped a little and was able to get a very slow stream of coolant to come through the tube maybe 12" of flow, very slow then it stopped, a few tiny air bubbles did come through, but I'm still not seeing the flow I would expect.

    I'm assuming if the flow is not enough, I will get some kind of warning light or the temp get's too high.

    Any thoughts or suggestions?
    Thanks
    -andy

    ******** SOLVED **********
    After some more digging on previous posts I had to do the following.
    1: While in IG-ON mode (two press of the power button with foot OFF the brake)
    As the pump is running squeeze the inverter hoses Start with the one going out of the Reservoir. You can also jack up the side of the car and try the two going to the engine near the inverter drain plug.
    As you squeeze you should hear a different sound coming from the pump.

    2: Try bleeding squeezing and maybe take a 10 minute break (just long enough to post on this site).

    3: Try bleeding again, make sure the bleed valve hole is not plugged (In the bleed valve, you can unscrew it to verify).

    4: When bleeding make sure the valve is open at least 1/2 turn 1/4 turn might be too little.

    After doing all of the above, and then putting in another 4-8 ounces of coolant into my reservoir, finally fluid started to flow at a good rate through my clear plastic tube from the bleed valve back into the reservoir. I could also see the fluid running / bubbling in the reservoir.

    Note: Once you have the bleed process completed, and if you have too much fluid in the reservoir, simply bleed the down what you don't need.

    I think the key to this processes is patience and keep trying until it successfully bleeds and pumps the fluid correctly. If the pump is running, it will bleed.

    -andy
     
    #1 AndyFromWI, Aug 11, 2024
    Last edited: Aug 11, 2024
  2. Tombukt2

    Tombukt2 Senior Member

    Joined:
    Nov 29, 2020
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    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
    Yeah just don't bother with the bleed fitting You can do above Just leave the bleed fitting alone leave it connected where it sits in front there of the inverter I don't even crack mine fill it up like you're supposed to squeeze the hoses while you're feeling if you want like milking a cow and then push the brake hit the button ready the car the pump is running squeeze squeeze squeeze some more All of a sudden you hear a big glug glug glug in the pump running real funny like it's drowning which is exactly what's happening now you see your reservoir go down a bit and you hear the water moving in the tank if it's a new pump and now you top it off there is no reason to crack the bleed fitting at all and if you do it may be crusty and need to be rodded out with a piece of wire or something