2007 intermittent red triangle

sounds like it's overheating

 

You should check for low coolant (check the radiator not the reservoir) and possibly a water pump issue (belt as well). It does sound like it could be an overheating problem.

 

You lost the water pump belt. Or the water pup has failed. be careful as the car has no temp gauge and an over heat is the quickest way to blow the motor. The little aluminum cylinder head will not tolerate an over heat. You may get way with it for a while if its very cold outside.

You have to remove the black plastic cover over the radiator to check the engine coolant level its like 3 screws to remove the cover under the cover is the rad cap. If the coolant is low its because the engine water pump is blown and leaking.

A G2 Prius with that much mileage needs top be hyper maintained and hyper monitored.

 

I dont mean to harsh you my dear just trying to help. A car with that much mileage needs alot of checking its blood pressure if you know what I mean.