mystery coolant loss heat outlet strange

So I've got the '09 having trouble with heat I've been fooling with this for a couple of weeks now. I put water in get it all filled up no cap on the system nothing let it sit overnight. Come out in the morning and water will not be at the top of the filler neck I squeeze the bottom hose and I can hear the water right level with the filler neck tube that's parallel with the ground or the part that sticks out not up so I add more coolant not much maybe a half a cup a little more to bring it to the top leave it If it doesn't move I cap it start the car go for a drive and heat is coming out weird in the center vents the one on the right is very hot The center vent on the left is 20° cooler and the vent on the far left of the dash by the driver door is blowing not air conditioned air but cool air not quite as cold as outside eventually all the vents will seemingly heat up but they're not all the same temperature they're similar as above but they're warmer while driving around for 45 minutes something happens The system breaks prime and the air coming out of the vents I feel it going cold I don't hear a air damper moving or anything changing in the heating system We are on high medium fan and that's it. Also I notice unlike my other three vehicles this car no longer keeps the ice engine running when there's a call for heat like my other cars but sometimes that works sometimes it doesn't The call for heat and the engine running It's kind of weird. Then if I go for a drive for this 45 minutes the heat will stop working and then all of a sudden the triangle will come on and go off along with the MFD card display turning red with a thermometer in it and it's screaming at me that it's overheating then it goes off stays off for oh a few seconds a minute comes back on again I drove 40 miles the other day at 70 miles an hour under these conditions and when I arrived where I was going The hoses are holding pressure just fine they're pumped up tighter than basketballs nothing is hot except the output hose on the driver side of the radiator or the output of the engine where it drops into the radiator drops down and supposed to go through the bottom hose or something The bottom hose is only hot halfway up the hose between the radiator and the engine or the thermostat connects. I've gotten so good at this I can crack the cap and let pressure out without losing water takes a few seconds and then when I open the system and look in again now my water is down where it was a few minutes ago below the filler neck and I add 4 cups very slowly something like that half of a 2 l bottle bring it up to the top make it sit there for 20 minutes doesn't drop I cap it. I noticed that because I'm getting this so full sometimes when I initially start to drive I think air or something is blowing off into the recovery tank which then blows off into this other hose that goes straight in between the two fans and drops on the plastic. But somewhere I'm losing water and when it breaks prime in the radiator cap it will not pull any water from the reservoir obviously but I cannot find where the water is disappearing it's not in the oil I don't think it's in the transmission if there's a cooling device in the tranny and inspecting all over the car for permeated hoses or anything I don't see any hoses that are letting any water directly through their rubber or connections they all look pretty original very clean black not turning white nothing I'm just trying to figure out where this water is disappearing to and the car never overheats has been no pinging going up hills with the gas pedal near the floor just to see if it does nothing car runs impeccably the only codes of the permanent PO420 and I get the code every so often for the cam and crank being out of alignment I clear that and it takes weeks for it to come back I'm sure it has nothing to do with my heat and water.

 

Pump sounds great It's original I'm sure of it I'm wondering if the impeller on the other side that we can't see of the pump is steel or something like that could it literally wear away in 500,000 mi like the impeller have no fins and just be a flat piece of steel spinning haha but water seems to be moving everything is quiet as far as I can tell there's no blown head gasket no codes for misfires but I'm going to pull the plugs and smell for cool and all that good nonsense I am expecting something like this at this kind of mileage I'm at like 555K in this car I'm willing to put another engine in it or pull this one out and take it apart and fix it and drop it back in. But everything sounds reasonably quiet not a whole lot of racket or anything going on drives good like I say every so often when the oil gets dirty I'll get the cam and crank sensors are out of alignment or chain stretch or whatever we're calling that and then 500,000 miles I would think there is some chain stretch for sure

 

No I'm not certain but I'm pretty sure and I put the car up on ramps and look up under the vehicle I can find no hoses no areas of leaking of coolant or oil for that matter for the $55K on it It's a sealed system still there's nothing in the oil It's clear as day practically very nice color I've squeezed and messed with every hose looking for permeated hoses All of these are original I don't want to just change all the hoses on the car doesn't seem to make sense there is a hose right up under the intake that very rarely looks like there's a little drip around it it's a little short thing but certainly not to equate missing 2 cups of water or better in 20 or 30 minutes of idling or going down the road funny thing is when it sits in the yard and idles for hours I can't see anything going anywhere even with the radiator cap off but it will not stay filled to the top of the filler neck or the hole is to head to the reservoir with the car running for extended periods of time with the cap off like in my Corolla the radiator starts to heat up the water or the engine heats up the water in the radiator in the water rises and dumps over where the cap would be because of the expansion and heat in the Prius and I'll be waiting all day for this to happen.

 

Yeah I have to watch the oil on this car because when it gets dirty the sensors for my cam and crank go wonky and I get to whatever it is the 16 code for the cam and crank not playing nice together or the sensor saying so there's nothing happening in the oil that's beautiful and it's coming up on a change that'll be next I did have codes for misfires the other day but they have popped up random over the years every couple years I checked everything and cleared them I've been running the crap out of the car the last few days The only code that's there is always is the PO420 after the rain stops tomorrow I'll probably pull the plugs there at about 50,000 and take a look maybe just get a new set even though they're 100,000 mi plugs they've been in there a minute You're so we'll read them see what we got. I went out this morning 20 minutes ago car's been sitting for 14 hours The hoses are still pumped up like basketballs I went ahead and opened the cap because it's dead cold and water is standing at the top of the filler neck and some blew out over the filler neck and onto the plastics on the bottom under the radiator so I'm letting that dissipate right now The cap is off that's sitting right at the top at the hole ready to go to the reservoir I let it stand for about 3 minutes didn't move I put the cat back on reservoir is full this is what I expect to see and we'll go for a drive in about 30 minutes