Adamnnn

My CT just hit 100k miles not too long ago. Did 100k service and Lexus did a coolant flush. I don't think they messed with the inverter coolant though. The coolant is on the low line, for both the Inverter and the ICE reservoir. No lights in the dash, I was just curious to see the oil level and checked the coolant this time. Could it be that dealer didn't fill up to fill line, or is it just disappearing------also, its only been 5k since I flushed it.
Engine seems to be running okay. No codes.

ICE reservoir

Inverter Reservoir

E46CT

I think that's just the low limit line, meaning don't let it drop below that ever. but you can add a little water to put it in the middle or a bit higher if you want. Check to see where the line is when the car is at its hottest. given that you recently fiddled with the coolant 5k miles ago, it's not abnormal for the level to drop a bit as air bleeds out. usually you need to re-check and re-fill the hours/days immediately after the coolant refresh.

I used to (and still do to some degree) specialize in cooling systems on BMWs.

Adamnnn

Thanks for the feedback E46CT. May add some distilled water to it just until I get it back to the dealer to add some more. I may buy some while I'm there. Will post to thread if level keeps constantly dropping~

E46CT

yeah i dont think it's a big issue. just refill and check a day or two after and periodically after that to make sure it remains stable

HOMER350

Personally i don't think its a big deal. But like he said, check it when it's hot...maybe it will be at the full line. If not, then add a tad bit (after it cools down again).

The "low" line doesn't necessarily mean your low, its just at the lowest acceptable level. But it should fluctuate between low and high depending on operating temp.

Adamnnn

I just went to look back, and the regular coolant level is fine. Well above the Low line. the Inverter is low. It’s never been changed in it’s lifetime. I will probably do this soon.