2010 Prius Overheating

It honestly sounds like you've still got air are you filling it up to the third letter on the jug You fill it up to there then you run the car and it should drop to the full mark that drop may take a few minutes you know Prius don't warm up and you know 4 minutes like a normal car and I didn't look at your mileage if it was stated in the original post these cars are known for water leakage into the cylinders and so on and so forth so don't know You've already had some misfire codes and changed plugs and all this and that maybe when you have the plugs out again you should be looking at the plugs for teeny tiny water mist vapor droplets they are very hard to see at my age I use a magnifying glass in my nose and if I smell the glycol on the plug I take my finger stick it on the plug end then touch it to my tongue to confirm that it is in fact pretty pure glycol like the 50% mix in your degas bottle. And then I go ahead and check the other three plugs and verify or maintain that they're clear clean whatever and then I know I have something quenching my fire in the given cylinder or I tasted this and smell this then I know then I start looking for an engine.

 

What was the miles when you bought it?

Could be a stop-leak product in there?

 

Back flushing doesn't mean it will be cleared.
Did you clear the radiator also?
If it ever had pretend stop leak, it's clogged. Along with other small passaged
for the head and engine...
White vinegar might help to clear that crap out. But you might need a new radiator,
possibly heater core. Radiator first.....

 

One stop-leak manufacturer recommends 50/50 water/vinegar, says it dissolves their goop. Then flush well with straight water. If you can extract a few blobs of the stuff (assuming there is some in there) test them with that mixture.

Also, once you're done, you've now got a system with a fair amount of residual straight water. Trying to get that back to 50/50 mix with pre-mixed coolant (the recommended Toyota Super Long Life coolant ONLY comes pre-mixed) is nigh impossible. Consider using coolant concentrate, say Toyota Long Life coolant (without "Super"). It's service interval is half though. There's some thoughts on that in my signature (on a phone turn it landscape to see signature).

 

Why did you replace the water pump last year?

What engine water pump did you purchase? Was it an OEM pump?

It sounds like a bad water pump to me.

 

Was the headgasket replaced? If not, is it losing coolant?

SM-A536V ?

 

That's water expansion from getting hot getting too hot and it'll expand too much and it blows out the Degas bottle lid or a cap there's an o-ring in there that's why you're undoing it off the click and then you're turning turning turning turning and it lifts up off of there and he flip it over you see that o-ring that goes in and up and down in the bore. Mac creates the seal like your radiator cap and then I guess once you reach a certain point it can blow through the pressure relief in that cap and then it comes out of that little nipple that's facing the right side of the car and squirts out and I imagine some steam comes with it and it looks quite funky when it's doing it quite a bit this is why you feel to the third mark up on the digest bottle what's it the p mark or something and then when it's done and everything is settled it should be at the full mark I'm imagining this be warmed up obviously after you drive in the air and all rises to the top the level of the coolant falls to the full mark then you get in your driveway or park somewhere and you look at it you see it's on full so it's dropped from p to f or whatever that is and you leave it then when you come out in the morning you should lift the hood or whatever I just leave the hood up my property in the morning when I come out I look at it to see dead cold how much everything is shriveled up I'm a little below full usually

 

Sounds like your inverter coolant pump is not pumping if the reservoirs full the specified for the inverter coolant pump which is opposite where the coolant goes for the engine complete other side of the car both reservoir should be pink color indicating pink or reddish fluid is installed which is just the Asian branded coolant at Walmart or wherever you go Toyota dealer pretty much all very similar nothing to worry about too much but if that fluid is not moving and it's getting warm enough it will affect inverter and thereby hybrid performance a generation 3 may be more finicky than a two in this regard but in any case you need to get that fluid moving there's a reason it's not moving and it's stagnant and getting hot generally one would be looking towards the electric pump get your hand to where the hoses are for that pump one hose will usually be quite warm in the other one will be quite cooler indicating that the pump is not working being called upon the operate or something

 

Thanks for coming back and reporting the fix.

What water pump did you purchase this time?

.

 

It is very unlikely that the engine coolant temperature (ECT) sensor caused the engine to overheat. So you say that the thermostat gasket blew out? If that happened, coolant was leaking out. If the coolant level got low enough, the engine would overheat due to the lack of coolant, and the high coolant temperature or lack of coolant would affect the impeller in the water pump.

It sounds like you have severely overheated the engine, which will lead to failure of the head gasket. I would start looking around for a replacement car or an engine replacement.

 

In most cars, the idea of the ECT sensor causing overheating would be out in left field; it would be the wax pellet in the thermostat controlling the temperature, and the sensor doing nothing but reading the temperature for the ECM to use for things like fuel mixture control.

In a Gen 3 it's maybe not quite as far in left field, as the water pump is variable speed and the ECM tells it how fast to run, and may look in part at the ECT reading to do it. I still wouldn't leap right there as a cause for overheating though.