The most common reasons a Toyota Prius is overheating are a coolant leak (water pump, radiator, hose etc.), the radiator fan, or a failed thermostat. Coolant leak (water pump, radiator, hose etc.)

How do you know when a Prius overheats?

The following may indicate that your vehicle is overheating: l The high coolant temperature warning light comes on or flashes: The engine may be overheating. l “HYBRID SYSTEM OVERHEAT” is shown on the multi-information display: The power control unit may be overheating.

Do Prius have alot of problems?

According to some owners, their vehicles have experienced a wide variety of engine-related issues, such as a blown head gasket, engine hesitation, engine failure, overheating, and stalling.