Prius heater not getting hot enough!

I think in that car and even maybe in my generation too when you put that defrost on it automatically puts the compressor in the mix not like it's air conditioning but still it's on that's why you're feeling the cold turn the defrost off heat on high not 85 but HI and let it run a few minutes like that I can't imagine you're running around all the time with the defrost on usually I only need that a couple minutes in the morning and as soon as the cabin gets warm yeah anyway. But bubbles are yes are a bad thing so now when you filled it up to be and you've done the driving and what not has it fallen down to the full mark? If so that air should just work its way out I mean I don't know how long this has been you've done all this work but generally a few drive cycles I don't mean 4 minutes. Should get it

 

If your car has air trapped in the cooling system, it will likely result in no heat because the air bubbles prevent the coolant from circulating properly through the heater core, which is responsible for generating warm air in your car cabin; essentially, the air pockets block the heat transfer, leading to cold air blowing from the vents.

 

Did you fill the system quickly? That's the issue.
You should drain the system, and save the coolant!
Then, SLOWLY, about a cup or two at a time, fill the system. Wait 5-10 seconds,
then add more. You'll hear the coolant draining, and the air being pushed out.
It will take you longer to fill it, but you won't have air in the system.
And yes, fill to the B line. Start the car and let the engine run until it shuts off.
The level should go down to the full line, more or less. Add coolant to just about the full line.
And you're on lever ground, right?

Then drive the car a mile or so trying to keep the engine running the whole time.
Then park the car and let it cool. Check the coolant level. Top off as needed.

Filling too fast doesn't allow the air to be pushed out, it just caused air pockets.
This happens on other vehicles too. Filling slowly and a little at a time allows a gap in
the hose and lines so the air can be displaced.

 

My first thought is stop-leak product was installed by seller. See also the following postscript.

 

PS: NEVER NEVER EVER PUT THAT SO CALLED STOP LEAK/HEAD GASKET SEALER IN
THE COOLANT SYSTEM!
IT DOES NOT WORK! IT ONLY CLOGS UP THE COOLANT SYSTEM....

 

You need to fully purge the air from your cooling system.
Why did you change the water pump & thermostat? Was the car overheating and are you currently monitoring the ECT?

It would be difficult to purge the air from your cooling system, if exhaust gases are being constantly pumped into your cooling system. Ergo the stop leak in the cooling system, so the previous owner could sell the car. The auto parts store has a chemical dye that will react to exhaust gases in your coolant. It's not a 100% accurate test, but it'll give you an idea of what your dealing with.

Sorry.....

 

It's extrememly rare exhaust gets into the coolant for the Prius.
By the time that happens, the engine is wasted.

And it's easy to get rid of the air in the coolant system. Best NOT to get any in if the first place.

 

Why did you change the water pump? Was the engine overheating?

It is possible that the new Aisin water pump that you installed is faulty.

 

See post 4

 

You're welcome /

 

Good to know that's still effective, vent or not.Our 10 has the white plastic clap you can partially unscrew, allowing air to vent, say during refill after a coolant drain. It seemed effective when I did our coolant change in 2020. Just left it open while filling, till I saw solid coolant flow.

I suppose you could splice in a t-connection with a screw cap on the side spout. They're referred to as "Flushing Tee".

 

See Post #4.....
Have you replaced the thermostat?
If the hose to/from the thermostat is NOT hot, obviously the coolant isn't flowing.

After replacing it, with a TOYOTA thermostat, SEE POST #4.....

 

I don't think the two brands of the pump are a huge issue Asian and Asian and their toy that's one of Toyota's companies or it was I don't know what the status is right today but something along those lines now Toyota has a lot of companies they use that they don't own and that they don't have parts made predominantly for them they make parts for everybody just like nippondenso makes all the electric from my Italian scooters. Not having enough water in the system in air trap will cause the same problem water won't move through the system because you can't pump air everything looks like it's full You're getting a little squirt when you take pressure off the cap and all of that but really nothing's happening so you got to make sure you are super full of water coolant etc and that it has a chance to move or else it's not .