Prius Gen 3 overheating Uphills

After replacement of the pump did you get all the air out of the system? If so how did you get the air out of the system?

 

How long between the warning light and when you checked that temperature?

The warning light doesn't come on for engine temperature until 120 ℃*. So if you had the light on and you saw the engine coolant at 106 ℃ right away, then it wasn't the engine over temperature, but one of the other coolant temperatures in the car. Did you check all the inverter and MG temps?

On the other hand, if you saw the warning light and then the engine had a chance to cool some before you read the 106 ℃, then maybe it was the engine after all and it did hit 120 ℃ at that earlier point where the light came on.

* The Gen 3 engine has two coolant temp sensors. I've tested this for the one that's in the EHRS return hose. I haven't done the same test for the one in the cylinder head, so possibly that one could have a different trigger point for the warning light. But I know it's higher than 107 ℃.

 

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My gen 3 engine automatically shuts down when its getting hot because my water pump failed, but i don't think that gen 3 engine head gasket can survive at 120 degrees or even the engine because its all aluminium, cooling fan comes at 95️

 

"It can be estimated that the temperature at which gasoline engines start burning gases can reach 4,500 degrees Fahrenheit from a number of factors including the shape and load on the engine, the position of the engine, and the degree of rotation at the point of maximum output. The temperature can be as high as 6,000F in extreme conditions."

 

Yes, the repair manual covers that. If the ECM is reporting a water pump failure, it will then do an abrupt engine shutdown if the temperature reaches 105 ℃.



If there isn't a water pump problem on report, then nothing shuts down at that temperature. But get to 120 ℃ and you'll see the red thermometer light.