Inverter coolant level

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by tkddad, Jul 3, 2012.

  1. tkddad

    tkddad New Member

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    I had my inverter coolant changed at the dealer last week (together with the regular coolant and
    transaxle fluid). I noticed that the inverter coolant level in the reservoir is at just below the low level.
    It also stays at that level even when the car is warm after a long drive and doesn't go up like the regular coolant does.

    1) Is it worth a 30 minute drive to the dealer to ask them to top it up? I did a simple search about the pink coolant and they are $28 a gallon, WOW.

    2) I had some Prestone in the garage. Should I just top it up myself? I read that it's not a good idea to mix them.

    Thanks.

    P.S. In case anyone is interested, the inverter coolant change is $150 at the dealer. The regular coolant change and Tx fluid change are $90 each.
     
  2. jdcollins5

    jdcollins5 Senior Member

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    The inverter coolant uses the Toyota SLLC (Super Long Life Coolant). You definitely do not want to top it off with the Prestone. Either way you are going to need to go to the dealer to either get a gallon of the SLLC or have the dealer top it off.
     
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  3. jadziasman

    jadziasman Prius owner emeritus

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    How low is "just below"? If it's just a couple of mm below the low mark then all you'll need to do is add about 10 ml of distilled water and you'll be fine. At least half of the SLLC is H2O - n'est-ce pas?

    OTOH, if it remains at that level it is now - meaning it isn't decreasing over time, you are needlessly fretting about it.

    I topped off my inverter coolant level with distilled water when it was just slightly low last year and it's been fine ever since - reads at the high mark when hot. There's not much difference between the high and low level marks anyway.
     
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  4. tkddad

    tkddad New Member

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    Thanks for the reply. I just had a closer look. The level is about 3 cm below the low level. I will make a trip to the dealer tomorrow.

    I was wondering whether the level would go up when the engine is warm. It apparently stays at about the same level whether warm or cold.
     
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  5. jadziasman

    jadziasman Prius owner emeritus

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    It will go up - slightly. I see it rise from halfway between the low and high marks to the high mark, which again is practically nothing at all if you look closely at where the low and high marks are.

    And - I only see the level rise when the temp outside is above 90°F, like today. On a cooler day - bubkis!
     
  6. Patrick Wong

    Patrick Wong DIY Enthusiast

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    3 cm is more than one inch. Perhaps you meant 3 mm? If the level is really 3 cm below the low level then it is seriously low.

    Especially since you reside in an area with winter low temps substantially below freezing, I would not encourage you to dilute the antifreeze with water. You need all of the antifreeze protection available.

    I also would not expect the inverter coolant reservoir level to change very much as the drivetrain warms up.
     
  7. tkddad

    tkddad New Member

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    Yes, it's 3cm, a little more than an inch. I went in this morning and they just top it up. The service guy mumbled something about air pocket.

    Thanks.
     
  8. jdenenberg

    jdenenberg EE Professor

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    He meant that there was a remaining air bubble in the Inverter coolant loop after refilling the coolant. When it cleared, the coolant level dropped to fill in the space. This is a common problem in the ICE coolant loop after a drain and refill.

    JeffD
     
  9. tkddad

    tkddad New Member

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    How long does the air bubble stay in the system? It's been two months after the inverter fluid change and the level
    is now clearly below the "low level". I have been on vacation for 4.5 weeks so the car has been sitting in the garage
    during that time. Would that cause the drop in the level?

    Thanks
     
  10. jadziasman

    jadziasman Prius owner emeritus

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    Then there must be a small leak somewhere. Once topped off, there shouldn't be any decrease in the fluid level.

    You're going to have to do a pressure check with dye to locate the leak.
     
  11. Patrick Wong

    Patrick Wong DIY Enthusiast

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    It sounds like the inverter/transaxle coolant loop has a leak. I suggest that you first look at the inverter, then get under the car and look at the transaxle case and associated coolant hoses, for a pinkish powdery stain.

    Or take the car to your dealer and ask them to check the inverter/transaxle coolant system for a leak.
     
  12. tkddad

    tkddad New Member

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    Thanks for the reply, gents. I got under the car and there is some pinkish residues around the seal of the transaxle case. The hoses to and from the inverter looks ok.

    What could have cause the leak? I don't mean to sound skeptical but there was no leak for 100k km before
    I went into the dealer for the transaxle fluid change and inverter coolant change.

    When they changed the transaxle fluid, don't they just drain and refill through the same hole? It's not
    like that they have to remove a pan and then the seal was not put back in properly when the put
    the pan back in. Am I making any sense?
     
  13. edthefox5

    edthefox5 Senior Member

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    The residue may be from when they dumped the Inverter coolant. Its dump bolt is one of the large bolts under there pretty close to the dump bolt for the trans. If you suspect a leak I suggest you hose off the area in question with carb cleaner and rag it clean then any further leaks will be easily detected. Also they use a pinkish colored sealer between
    the cases of the trans. You may be able to see it squished out so don't mistake that.


    It may not be leaking it may just have a bad air lock caused by shoddy bleeding. That takes a long time to disperse and over time as air evaps it leaves a void and fluid shows low. Takes a long time to fill it back up. Heard many reports of that on this site.

    The way to check for air lock or a failed pump is to make the car READY and open the reservoir and look for turbulence in the coolant reservoir reflecting pump flow. Should have good and steady movement of fluid. Or with the car in Ready listen to the pump itself.
    Wait till engine shuts off so its quiet. That little black electric water pump can be found right behind the drivers side headlight. It has 2 hoses hooked to it. One coming one going.
    Put the car in READY and wait till the engine shuts off so its quiet. Then put you ear as close to that pump as you can and listen to it. It should be smooth and have a soft whine to it like a aquarium pump. If any gurgling or intermittent sounds like the pump is going dry for a second or 2 there's air in it. Should be smooth and quiet.

    If quiet and good steady turbulence then there may be a small leak. Never heard of a Inverter coolant leak before. Becasue if there's a leak it will have air in it also.

    There's only 2 mechanical openings for the Inverter system. The dump bolt under on the trans and the air bleed petcock. There's a air bleed petcock up top they must use. Maybe they never tightened it. If not it would leak and the Inverter coolant would be full of air.
    Not sure how handy you are but you have to take the black plastic TOP front radiator cover off. Its very easy. It has 6 screws. Need a phillips screwdriver. While unscrewing the screw snake your hand under the screw and push up on the screw. Comes right out. The petcock is in front of the Inverter lower left. It has a screw on cap. See if that's tight or see if you can loosen it by hand a bit. If if its loose it must be tightened by tool. If loose take it back as air has gotten into the system and they have to bleed it again.

    Good Luck!
     
  14. tkddad

    tkddad New Member

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    Thanks very much for the detailed explanation.

    The pinkish residue I saw was between the casings of the transmission. Maybe I am just seeing the seals.
    I will have a closer look tomorrow.

    I had already check to see the pump is working after I googled and found out about the pump recall/service
    bulletin for the 03-07. Mine was an 08. There are turbulence inside the reservoir. I have also listened to
    the pump as you have suggested and it was smooth without any hiccups. I will look to make sure they
    tightened the air bleed hole tomorrow.

    I will probably just take it back to the dealer to top it up as I don't have any of the pink coolant.

    Thanks again.
     
  15. edthefox5

    edthefox5 Senior Member

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    Ok thanks sounds good. That pink sealant has thrown many people!
     
  16. tkddad

    tkddad New Member

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    Went into the dealer today. They checked for leaks and found none.

    They also claimed that the level is ok and they would not bother topping it up. Right now it's just a touch below the
    low level.

    They sent out the service "foreman" to talk to me. He said the level would fluctuate 1/2 inch depending on the
    temperature and as long as the level is not about an inch below the low level, I should be ok. If there were
    leaks, the pink coolant would "crust" up so it is very easy to spot.

    I have checked the level when the engine was hot and cold and I don't really see any difference in the level. I have
    made a mark at the current level and will check it periodically.
     
  17. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I disagree with the suggestion that the inverter coolant level will fluctuate 1/2". I live in an area where high summer temps can be 110+ degrees while low winter temps are at freezing. The inverter coolant level will remain pretty constant regardless of the car having been driven for hours, or with the powertrain cold after resting overnight.

    Instead of arguing with the dealer staff about this or living with a fluid level below the minimum mark, why not just buy a gallon of Toyota SLLC so that you can fill to the full mark, and see what happens.
     
  18. 2009Prius

    2009Prius A Wimpy DIYer

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    I am amazed the dealer won't just top up the fluid to make the customer happy. I went to the dealer to top up the engine coolant twice, after they resealed the timing chain cover.
     
  19. uart

    uart Senior Member

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    Ok dumb question, but I've never noticed a "low level" mark on the reservoir. Does it indeed have both a high and a low level mark and I've just never noticed, or is there but a single "level" mark there?
     
  20. 2009Prius

    2009Prius A Wimpy DIYer

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    There is a Full mark right above the thick seams and a Low mark right below. Why Toyota put those obtrusive seams there to block the view of the fluid level is way beyond me.
    [​IMG]
     
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