The cooling system’s thermostat is simply a valve measures and regulates the temperature of coolant. The purpose of coolant is too cool off the engine as it burns fuel. It does this by circulating through the engine, absorbing heat, and carrying it to the radiator. Once in the radiator, the coolant is cooled by the air stream from the vehicle’s grill and then re-circulated through the engine. The thermostat’s job is to determine when the coolant has absorbed enough heat from the engine and can be released into the radiator and vice versa. If it’s not hot enough, the thermostat will seal the radiator, forcing the coolant to circulate throughout the engine. If the coolant is too hot in the radiator, it won’t be released. If the thermostat is stuck open, the engine will run cooler than it should and use more fuel. Conversely, a thermostat that is stuck closed will cause the engine to overheat and could cause serious damage to the engine. Symptoms of a bad thermostat include a knocking sound when accelerating, low temperature gauge readings, overheating, decrease in fuel economy, and a malfunctioning heater. If you experience any of these issues, bring your car in a soon as possible. Lake Norman’s service and repair center is located in Mooresville, NC.