No heat, coolant normal, no codes, AC blows

Hhaha no worries. Your anecdote of observed failure before error code presentation, combined with ChapmanF's pointers on the sound, seemingly confirms all I need for this. I'll follow back up soon here after I get this bad boy swapped out!

 

Weekend update. I successfully replaced the coolant control valve, and since then I haven’t heard the “hunting” sound, so I call that a win. That said, cabin still is not functional.

Lost a bit of coolant so went through quite a research journey trying to figure out what coolant to get. Conclusion was:
Red is ok, but non-silicate HOAT pink is best.

Engine is now in the cooling down phase of the bleeding/burping effort that was predicated by 20 mins of inspection mode with coolant in an overfilled funnel and periodic opening of the radiator bleeder valve.

 

Also relevant. I watched the engine temp get up to 200F, so that tells me the circuit is getting warm enough to blow heat into the cabin.

 

Engine block got down to ambient enough temp in 2h. Filled the radiator to its target amount.

Took the car for 15-20min drive with the OBD2 scanner in to monitor coolant temp. Did some F1 style left-right tire warmups to move any stubborn bubbles around the coolant circuit. Over the drive, car temp got up to 192F max after I floored it, but in all instances of elevated temp it cooled off quickly to 184F. I was pretty much just flooring it and coasting down, so I’d consider that as difficult of a heat load as possible. Coolant system seems to be working in keeping the engine at nominal temps.

At the end of the drive, when putting it into park, I did notice the pump sound of the car pumping hot coolant into the tank, which I *think* previously was when I would’ve observed the hunting sound.

Will put some more coolant into the radiator in the morning after the block is cold soaked.

In any case, the journey for cabin heat continues.

 

Per No heat - what's next? | PriusChat also significantly assisted by ChapmanF, I checked the temperature control door.

I don’t seem to be able to adjust temperature while the fans are at zero so I let them to low, then went from low to high, and I do hear some sort of very faint servo-ish sound coming from the driver footwell area. I assume that’s the temp door sound being referenced but of course willing to hear otherwise.

 

Found another thread referencing the ability to visually check the temperature blend door, so I'm going to attempt that tonight.

Can anyone assist in other conditions to check? Did a cursory feel check on the hoses after I replaced the valve and ran the engine for 15ish mins, and I think I recall that the main radiator hose by the valve, as well as the topmost hose of the valve all felt warm. Any other hoses I can spot check to help guide where the next issue might be?

 

Long trip today. About 40 mins of driving so far. Coolant temp is reading 200F in 63F ambient. Seems to be confirmation that ending coolant loop is indeed doing its job, though based on some other threads I’ve been reading about target temps of 190 it could be better, but I haven’t been able to find any official optimal temp documentation.

Gonna cop a feel on some hoses today when the drive is done

 

Team update - we now have heat again.

After replacing the broken 3way valve, bleeding the coolant lines, and running it on a 100mi road trip, heat did not work. Felt all the lines and some were HOT, some were warm, some were cool, as they were seemingly supposed to be, and the control door servo in the cabin was working, so I was head scratching. Lost time, and just let the gf drive it for the last couple weeks.

Yesterday, she told me she tried the heat on a whim and it somehow worked. No a clue on the world, but I’m not here to complain. Based on symptoms, sounds like some of that foamy material seen in other threads clogged something up but knocked itself loose ¯\_(ツ)_/¯