What is an engine thermostat?
 While all engines can become too hot, if your thermostat isn't working correctly, your engine's well-being is at serious risk. The engine thermostat, often simply referred to as a thermostat, regulates the engine's operating temperature within an optimal range (typically around 195 to 220 degrees Fahrenheit).
How does a car thermostat work?
As a temperature-sensitive valve within the cooling system, a car thermostat responds to changes in coolant temperature. Understanding how it works by the following breakdown steps:
- Closed position (cold start)
 
Initially closed to help the engine warm up quickly.
The engine generates heat during operation.
A temperature-sensitive element (usually wax) causes the thermostat to open gradually.
When open, coolant flows from the engine to the radiator.
- Maintaining optimal temperature
 
Adjusts coolant flow to maintain the ideal engine temperature.
Continuously adjusts to prevent overheating and ensure efficient operation.
Signs of a bad thermostat
- Overheating: The engine becomes excessively hot due to a stuck-closed thermostat.
 - Low or fluctuating temperature: A thermostat stuck open results in a cooler engine, affecting fuel efficiency and heating.
 - Temperature warning light: Illuminates to indicate engine overheating due to a faulty thermostat.
 - Poor fuel efficiency: Stuck-open thermostat reduces fuel efficiency as the engine operates less efficiently at lower temperatures.
 - Inadequate cabin heating: Insufficient cabin heating in cold weather with a thermostat that's stuck open.
 - Coolant leaks: Gasket or sealing issues can lead to coolant leaks.
 - Rapid temperature fluctuations: The gauge shows rapid swings between hot and cold.
 - Engine running hot at idle: Higher engine temperature during idle or in traffic due to restricted coolant flow.
 - Slow or inconsistent warm-up: Longer-than-normal warm-up times, even in moderate weather.
 - Inconsistent heater operation: This affects the performance of the vehicle's heater, causing inconsistent or inadequate heating in cold weather.