High Coolant Temperature Warning Light

Lots of people have had similar problems with this engine and gen3 models. I would take it to hybridpit. At minimum, you might have a bad water pump but maybe not if the head gasket has blown.

In reality the oil burning followed by running out of oil followed by overheating means you need an engine or get rid of the car.

 

These are warnings of serious problems- the engine is not likely to last a lot longer. Might already be time for a full replacement.

 

Anymore info on that, say misfire codes?

 

Sounds like a sticking or slowing rotor on the electric water pump.

 

Do you know which cylinders the ignition coils were changed on? Where I'm going:

It's common for gen 3's and Prius v's which are mechanically similar, to have head gasket failure, somewhere between 150K~200K miles. Codes that often manifest are for "misfire":
P0300 (general misfire code)
P0301 (misfire cylinder one)
through
P0304 (misfire cylinder four)

Typically the head gasket failure is at the exhaust side, between cylinders one and two, allowing coolant to seep into either cylinder, though more typically cylinder one.

What's the miles on it?

Has the EGR (Exhaust Gas Recirculation) system, including intake manifold, ever been cleaned?

It's fairly common for these head gasket failures to be misdiagnosed, and unecessary spark plug and coil replacements done, because it's easy and profitable for mechanics.

The other issues:

runaway oil consumption, likely due to low-tension piston rings Toyota used, till partway through model year 2014 with the Prius hatchback. Plus drain holes in the pistons that are prone to clog. Prius v also finally revised the low-tension piston rings, but your 2012 will have the low-tension rings for sure.

electrically driven water pump, that is prone to failure, somewhere between 100K~150K miles.

 

I would see engine high temperature, and oil burning are 2 separate issues. Not saying oil burning due to high engine temperature is not related...
Likely you have a failed engine water pump, and possibly a bad thermostat...
although I haven't seen a bed thermostat from this generation of Prius, but I wouldn't rule out the possibility and would replace it with water pump...

As for loss of engine oil...
I would check for oil leaks externally, if non or very light oil leak found. Then I would look into piston rings and valve seals...
I've replaced few valve seals, and seen greatly reduced oil consumption, but not to say you didn't have bad piston rings ..

Also, I wouldn't rule out the possibility of bad head gasket because of engine miss fire, but it also can be the end result of clogged EGR circuit if they haven't been maintained...

Just my 2 cents, but I would definitely check for fault codes first and address it accordingly...

Good Luck!

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Your EGR components, the cooler and valve, will be packed with carbon, reducing overall flow. The EGR passages in intake manifold that feed exhaust gas to individual cylinders are about 1/4” ID, can totally clog, completely sealing of what remains of the exhaust gas supply.

then engine runs hot, head gasket fails, allowing coolant to seep into cylinders, engine struggles to compress the uncompressible coolant, “misfires”.

toyota screwed the pooch with Gen 3 EGR introduction, didn’t test it sufficiently, and is dodging responsibility. For owners, the only workaround is an arduous disassemble and clean of the mess, say every 50k.

 

This car burns oil so bad it ran out of oil. Give me a break.

 

Yes, it did that, too. Clogged EGR and low-tension piston rings can work in concert.