How can a failing thermostat cause a Toyota Prius to overheat?

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How can a failing thermostat cause a Toyota Prius to overheat?

The thermostat regulates coolant flow in the engine. If it gets stuck closed, it can restrict coolant circulation, leading to overheating. What are the signs of a failing thermostat, and how can Prius owners test it?

Sandeep asked on 14 Feb 2025 16:01:04 pm

1 Answer

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Car Mechanic Expert - on 14 Feb 2025 16:05:38 pm

If the thermostat is stuck in the closed position, it can restrict coolant flow, causing the engine to overheat. Signs of a failing thermostat include:

The temperature gauge rising quickly.
Engine performance issues.
Coolant not circulating, even after the engine runs for a while.

You can test the thermostat by inspecting if the radiator hose stays cold after the engine warms up.