Dreaded P0A80 Code - Car Running / Charging Good.

Mixing coolant is not good. You run the risk of it jelling up, and not flowing.
But it's done.
If you fill it slowly, and a little at a time, you won't have to worry about air pockets because the coolant
will push it out.
If the coolant temperature is within specs, while driving, it's likely working correctly.

 

Yes there is a good flow entering from the top reservoir hose once the thermostat opens. Flow before the thermostat opens uses the thermostat bypass inlet. Even after the thermostat opens a majority of the flow returns via the big radiator hose.

Regardless there is a decent flow through the reservoir after the thermostat opens.

Due to the somewhat opaque plastic of the reservoir, I place a small led flashlight directly on the top of the reservoir to light up the inside, making the flow clearer.

A portion of the gen3 coolant flows (edited from a slightly different gen4 diagram)

 

nasty!

How fast if flows is hot it is and how much it need to cool.
It circulates mostly to the radiator, so you won't see a lot of movement in the coolant tank.
You might as well change the inverter coolant. It's the same coolant. Quicker and easier to change.

 

Yea, the inverter's not important......

Why would you disconnect the battery to do the brakes??? No reason too.
Just do NOT open the drivers door while you're working on them. And keep the key fob more than
20 feet away from the car.

I've replaced the rear pads a few times and the hubs and didn't disconnect the battery.
If you think a family member or friend might open it, put a note on the window and down across
the door handle that says DO NOT OPEN.....

 

As long as you do NOT open the drivers door, you will not have a problem.
If you open the door, the pump will activate and push the puck out if you don't have the pads in
and on the rotor.
It won't hurt to disconnect the 12v battery, but you don't have too.
You will have to rotate the puck to get it all the way back in for the new pads to work.
Make sure you align the pucks to the pins from the pad to fit in the slots or you'll have an angled pad
and rapid uneven wear.

 

When the pump activates, it puts pressure into the storage accumulator. There is always supposed to be pressure there, and the pressure there never pushes on any puck, except when the brakes are applied. If it did, the brakes would be constantly dragging.

However, a gen 3 also does a brake self-test, 90 seconds after shutting down. That self-test does apply pressure to the brakes, and will push any puck out if the pads and rotor aren't there to restrain it.