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Bleeding inverter coolant system.

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by andyprius, Jun 26, 2011.

  1. andyprius

    andyprius Senior Member

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    Summer is here, if you drive in 100 degree F weather, use your AC and drive up steep hills. Check your inverter coolant system for trapped air. The inverter pump cannot pump air. I had the LSC about 6 months ago and apparently the mechanic rushed the job and there was still an amazing amount of air in the system, I did this yesterday. Today I checked it again and no more air showed on my clear plastic tubing. Although I had to top the reservoir with 2-3 more ounces, so air could have expelled out of the reservoir and I would not notice it. A interesting thread by Edthefox titled "Better gas mileage"shows the importance of checking this system. Maybe you will also get better gas mileage.I believe this thread or Eds should be a sticky. :cheer2::D:cheer2:
     
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  2. Hal W

    Hal W New Member

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    What is the procedure for bleeding this system? Is there a bleeding fitting similar to what you do when bleeding the brakes. Hal
     
  3. andyprius

    andyprius Senior Member

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    Just search on PC for inverter coolant pump, you will find many threads on the subject. It is about a 5 min. job. PS To answer your question, YES, the same type of bleeder screw.
     
  4. edthefox5

    edthefox5 Senior Member

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    Ok here you go as best as I can remember Pats post:

    Need 2 gallons of SLLC.

    Get in car and without putting your foot on the brake push the power button.
    Open the hood and put your ear down behind the drivers side headlight. Take note of how quiet the inv pump is when its running. Like an aquarium pump. Remember that sound...tone.

    Shut car off.

    Jack up the front of the car and with a catch container open the inverter coolant plug underneath. I know you know where it is as you have been on this site as long as me. I forget a 24 mm socket?
    Take out the plug and be prepared for about a gallon of coolant.
    Dump it all and leave the plug out.

    Fill the now empty Inverter reservoir up with water and let it dump out the bottom. Were rinsing it out here.
    After a little of that lets really rinse the loop.

    Hand tighten the plug underneath. Fill up the tank. Turn on ACC as above for about 5 seconds. Get out and you'll see it sucked in the water you just filled the container up and you need more water. Top off container again.
    Kepp doing this 5 sec routine till the reservoir is filled. Don't run the acc mode for longer than 5 secs until you know the coolant loop is filled so not to run pump dry.

    Helps to have an assistant.
    When tank is filled with water run it in acc for a little bit. The pump will make unhappy gurling sounds as its filled with air. We are rinsing/flushing here. Just 20 seconds. Keep tank filled.

    Dump this rinse water. Let it dump out completly. Then tighten the plug underneath. Your done under there.

    Fill up reservoir with SLLC. Same deal. Fill tank with SLLC...Run acc 5 secs......fill...run acc till its topped off.

    When it appears its filled run acc and open up the bleeder thats
    right in front of the Inverter. My bleeder cap was really on there good. Don't break it off with a wrench. I used 2 water pumps
    carefully.
    Anyway run acc...open valve..gurlges & spits out a little..close valve...add more fluid to tank......open bleeder.... gurgles out..etc.
    Does not take long at all till it goes form gurgling to trickling out.

    After it stops gurgling and spitting out the bleeder start paying attention to the sound of the pump. When it sounds like it did before you started...smooth...quiet...your done. Its bled.
    Any loud sounds like hissing or gushing keep bleeding. Keep filling.
    Till its a nice quiet pump like before.

    Your done.

    Tighten bleeder cap. Top off tank. Rinse under the hood area that got coolant on it. Especially the front of the car.
    Total time is about 30 minutes first time.
    Really easy.

    Good Luck.
     
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  5. andyprius

    andyprius Senior Member

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    Edit: I used two wrenches.
     
  6. Patrick Wong

    Patrick Wong DIY Enthusiast

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    1. I would not bother to flush the system with water if the drained coolant does not contain debris.

    2. Only one gallon of Toyota SLLC is required when working on the inverter coolant system as the capacity is ~3 quarts.

    3. A 24 mm (or 15/16") socket is required to remove the drain plug. Do not confuse with the transaxle ATF drain plug which requires a 10 mm hex key socket.
     
  7. sorka

    sorka Active Member

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    I just changed mine for the third time. I use an airlift which makes this about a 5 minute job and no chance of leaving any significant amount of air in the system.
     
  8. edthefox5

    edthefox5 Senior Member

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    I put Redline water wetter in my inverter coolant last time I changed it, Had really strong movement of circulation in the reservoir looked like it was boiling after the change. The more aluminum salt dissolved in it from aluminum wear the harder it is to pump that fluid and less efficient it is for heat exchange most of the contamination is from the initial break in.
    It’s been really strong for 50000 miles after my first change. It’s that first change to get all the break in wear that really helps,
    Your good for a long long time after that first change.
    Just like the trans fluid.