Can't fill inverter reservoir after coolant drain

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by FantasticalMagicOne, Aug 19, 2019.

  1. FantasticalMagicOne

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    I had noticed that my inverter reservoir was low a few weeks back, when I was checking for something else and I topped it off. I read through a fair amount of posts here and decided to change the ICE and inverter pumps and coolant (thermostat, oil and ATF as well). As some of you may have read, the ICE work turned out to be an ordeal, but I've driven a few hundred miles since it's completion and it runs well.

    Yesterday, I drained my inverter coolant with the intent of replacing it after I changed the coolant pump (and bracket). The bolts I removed from the old pump had crystallized pink in the threads, and so did the drain plug. I cleaned it up and set it aside. I switched out the pump, reconnected the hoses, reinstalled the plug (with a new crush washer) and torqued it at 29ft-lb. When I poured new coolant into the reservoir, it fell to the ground (drain pan). I checked the drain plug, but there wasn't any fluid coming out. I dried the coolant on the car with shop towels and poured more coolant into the reservoir to ensure that what I was seeing was and actual leak as opposed to me simply spilling it. My coolant level hadn't moved since I topped it off a few weeks ago, and I've seen no leaks until I began to refill the coolant. Anyway, I'm not sure where to look to chase it down, but I'm suspect of the tank and/or hoses connected to it.

    When I first saw the leak, it seemed like it was leaking out near the bolt on the left, and when I got closer I could see that it was coming from above (not within). The picture on the right was as far up as I could see.
     

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  2. Raytheeagle

    Raytheeagle Senior Member

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    Could the tank have a crack in it?

    Sometimes when you disturb connections and equipment that is seasoned, it can be fragile.

    Or is the hose on right with the clamps on the hose in the exact same location (not offset)?
     
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  3. FantasticalMagicOne

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    I suspect the tank or a hose somewhere in the back. It's coming down quickly in the back, but I didn't touch anything back there outside of the lid to the tank and the drain plug.

    Are you referring to the hoses on the pump (sorry, I haven't had my daily intake of caffeine yet)? If so, they are in the same place (not offset).

    If it helps, here's a few more pics I took last night. When I realized the it was dripping down to the bolt, and saw it on that other part (shaft assembly?) I thought it may have been leaking there. I dried up the fresh coolant and placed dry shop towels on the metal above the bolt and then on top of the other piece. Poured more coolant in the reservoir and determined it was pouring down from above (note the droplets on the part in the last pic). The top of the towels were soaked, but not the bottom.
     

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  4. SFO

    SFO Senior Member

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    How much fluid are you trying to fill the reservoir with?

    The "FULL" liquid level line is near the horizontal plastic lip that goes around, or an inch below the reservoir shoulder.

    There is also an overflow tube in the rear of the reservoir, some have found a way to insert a funnel into when refilling, which causes coolant to leak out the back. Personally I don't see how this could happen, but it has.

    [​IMG]
     
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  5. FantasticalMagicOne

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    I thought about spilling it down the back, so I pour some coolant in a small paper cup and poured it into the reservoir very carefully as to avoid spilling it and the result was the same. I emptied it before I changed the pump, and need to replace the coolant. That is, if I can manage to resolve this issue and I'm in a bit of a time crunch to do it as I'm out of state and can't stay past tomorrow night (wed morning if I can swing it).
     
  6. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Sounds like the reservoir has a crack or hole in it, per post 2. If true it won’t be easy to replace the reservoir without first removing the inverter...
     
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  7. FantasticalMagicOne

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    Is there a way to confirm before a removal attempt is made?
     
  8. SFO

    SFO Senior Member

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    Have you checked all of the items touched during replacement, like the pump, drain plug, connecting hoses, etc?

    Finding the leak might be a two or three person job, one filling, and others looking with flashlights from all available angles.

    Seems odd that it would be the reservoir, as it was holding coolant the other day just fine. If it is the reservoir you should rule that out as quickly as possible, as finding/installing a new/used part could take some time.
     
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  9. FantasticalMagicOne

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    I checked everything that I touched and looked everywhere I could. It's not the drain plug and the coolant goes straight down to the ground - there's nothing near the pump itself. I will go out an check again. Removing the windshield wiper assembly will allow me a better look, correct? I don't have a 2nd/3rd person available.

    Time is something that I don't have. I'm out of state and cannot stay where I'm at past wednesday afternoon (even that's pushing my limit). There are 4 dealerships in the area, but I highly doubt they'll have this part stocked. I've searched for salvage yards near me and have had no luck there.
     
  10. SFO

    SFO Senior Member

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    Yes, removing the wiper tray should gain a better view. You might get better access to the reservoir by loosening/removing the needed inverter bolts and gently lifting/shifting it towards the drivers side of the vehicle, not sure how much that will help though.
     
  11. FantasticalMagicOne

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    Just found this looking in from the top (day light helps). Dried coolant with a drop of wet coolant on a hose under the inverter, the 2nd photo is just a zoomed in section of the first. leak 2.1.jpg leak 2.jpg
     
  12. AtkinsonCycle

    AtkinsonCycle Junior Member

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    Hello! I just changed my coolant and inverter fluid and noticed something odd. If I did not hold the coolant jug centered over the reservoir opening, coolant would run out of the reservoir vent tube and out onto the ground. Yes, I had the jug set so fluid would go into the reservoir, but it was coming straight out onto the ground. It happened to me twice before I figured out what was going on. Maybe you could check and see if you move where the jug is while you are filling the reservoir and move it slightly, it may go in where it's supposed to. I think the reservoir is shaped a little bit like the brake reservoir in that it has an internal baffle. The inverter reservoir has an area where if the fluid gets hot and expands, it has a way out. If your fill jug isn't centered right, the fluid goes into this area and out the vent tube. I have read my reply over and I hope it reads okay. I hope this doesn't sound like "Center the fill jug over the reservoir hole so you don't spill it..."

    I hope this helps!
     
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  13. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Or, use a funnel.
     
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  14. AtkinsonCycle

    AtkinsonCycle Junior Member

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    She did say she used a paper cup to fill it, so I am assuming she had it lined up okay. Well, sorry I can't help out more on this one. Good luck!
     
  15. FantasticalMagicOne

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    I found someone that used to work on cars (non-hybrid) to help me locate the leak. He was under the car, while I poured in the coolant and it produced a slow drip that fell to the ground via that bolt (still coming from above). I'm not worried about a slow drip in relation to making the 140 mile trip home. I bled the system without further issue, cleaned the coolant off of every part that it had been spilled on, reassembled everything, then drove it around the parking lot and it ran fine. I parked in a different space to gauge how much coolant I'd lose throughout the night, and there was nothing on the ground when I checked it this morning. I topped off the tank and took it for a drive without issue.

    I've no explanation for this. How does it go from spilling to the ground, to a slow drip, to no leak? I have no words.
     
  16. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Maybe when you were adding coolant, some came out of the overflow. Once you have the correct level established and put the cap on, no further coolant would escape.
     
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