Coolant Loss

The jug is probably cracked right there at that fitting look carefully with a flashlight sticking right on top of the jug and on the side the bottom front you'll find it I doubt things are leaking past the clamp. Usually the plastic of the jug is compromised

 

It looks like it may be and the system does make a certain amount of pressure so you want to keep an eye on it when you get it warmed up going somewhere for a while whatever and see what you have going on If it is leaking from pressure you need to get it replaced a cheap aftermarket one can be fine It's a Gen 3 so it's not going to be around that long no worries on cheaper parts the cheaper the better with this car actually better doesn't improve the car's chances per se.

 

Perhaps a new hose????? There reall isn't much to trim back and reattach.
And a new cap? That will likely stop the leaking. If not, you could remove the tank, clean
it really well. Then fill the tank and put pressure on it to find the leak. Then heat
an old screwdriver or something metal and melt the place(s) where the leak is.
Or purchase a new one....

 

You use non-springloaded clamp on coolant system. That is the most common cause of leaks. Spring loaded OEM clam expand and contract as the temperature changes. If the hose is not cracked, than just replace the clamp. Otherwise, replace both and the leak will never occurs anymore.
Always use OEM "spring hose clamp" on any car. There is a reason why Tesla, and all ICE cars still use this spring.
https://www.huyett.com/blog/hose-clamp-types

 

Rearranging deck chairs on the Titanic?

Oil Catch Can Update, 2013 w/ 199K | PriusChat

^ 190k+ acquisition with clogged EGR and broken damper plate twixt engine and transaxle.

 

Some of these cars seem a perfect candidate for o-ring removal and zero pressure coolant It's for big trucks and it stinks real bad I can't remember the name of it We were using it in the '80s and some Toyotas but basically you change your cap and the stuff runs zero pressure it just gets pump through it doesn't need the pressure for the added boil protection if you will I guess.

 

Any update? Did you find what was leaking? Were you able to fix it?

 

Probably head gasket. Whats the miles?

 

240 seems a bit high for 38 degrees operations. Could that K-seal partially clogged your radiator?
Well you'll find out in the summer months, if the car will consistently overheat.
Your radiator fan should be turning at that temperature - it may be dead.

 

It's probably a bad head gasket and engine coolant pump.

 

If You get the car really hot. And then you stop undo the bolts that'll allow you to lean your fans back so you can get your hand and run it across the lower core of the radiator assembly the upper one is for the inverter cooling and if you run your hand across that radiator core notice any cool spots usually they're in the middle That's the area of the radiator that's plugged by something whether it's the KC or whatever that area is plugged that area is not doing anything to cool the coolant in the radiator It's only getting cooled out on the edges where it's burning your hands That's where the coolant is flowing so you see at the top and the bottom of that center those little four five tubes at the most that's all the flowing from one side to the other so it's dwelling so long in the system it's not pushing the heat off I guess and then I guess you'll slow down and maybe there's not as much pressure on the system or something and it won't like the lighter it seems to cool take a look and see if something like that's going on of course the head gasket for this 2Z engine is the normal thing The KC would probably go to the head gasket and trying seal up the small drip that's quenching the fire when you start the car and have that death rattle in the morning so now you don't have that or at least as much but you're not going to seal a head gasket up generally by putting stuff in the water You might mitigate it a little bit but it's not fixed.

 

Well, you just added more work, and possibly money by putting that "stuff" in the coolant.
Now you have to clean out the radiator, real fun, and the heater core, more fun.
And clean out the block, and all coolant lines, and possibly damaged the coolant pump.

Just except that you have a bad head gasket. If you caught it early, you'll only need to replace it.
And hopefully the head won't be warped. And a rod is not bent....

 

The Pruis is different. I don't think anyone has reported coolant in the engine oil.
So that test is pretty much worthles for a Prius.
Get a pressure tested and put in on the overflow tank.
Remove the spark plugs, put pressure on the tank. It SHOULD hold that pressure, it
should not go down. If it does, you have a leak somewhere.
With pressure applied, look inside the cylinders. Purchase a cheap bore camera you and use
with you iPhone or iPad and insert the camera in each cylinder. If you start #1, you will likely
see coolant seeping in close to #2 cylinder. And maybe the others three. It seems most gaskets
fail between cylinders #1 and #2.

When the gasket first starts to fail, coolant will seep into the cylinder when the engine cools down.
That's why it knocks on cold starts. When it gets worse, it will knock when warm.

 

What I noticed I do see on the 2Z Atkinson engine when it is starting to fail and it's already rattled maybe one time let's say If you start monitoring your oil not because you're losing any If you look at the very top of the stick about I'll measure it tonight but it's about 3 in above the crosshatch full mark you will start to notice a brown dot start to form on the dipstick what that is is coolant vapor and oil and it's collecting where vapor would be down in that girdle pan area so that sticky mess that sticking to your oil dipstick is out of the oil area and in the vapor area and the drips that you're getting overnight into your cylinder as your engine cools down or during the day whatever shift you work. That vapor settles on the stick right where I'm talking about I'll take a picture of it and forward it to somebody who can make it post I guess I've been monitoring this in a 2010 2 Z set up right now. It is in rotation here driving daily and it is failing there is no question about it we're running zero pressure in the cooling system as of 4 weeks 5 weeks ago made a huge difference car runs very differently without pressure pushing the drips into the cylinder while the car is sitting and cooling but still we're on borrowed time . Replacement car ready to go in rotation as soon as we can blow this one up