Thermostat

Category: automotive

A valve that controls the flow of coolant between the engine and the radiator.

The thermostat is the "gatekeeper." It stays closed until the engine is warm (to help it heat up fast) and then opens to let the radiator cool it down. If it gets stuck "closed," the engine overheats immediately.

Common Examples

• The engine was overheating because the thermostat had failed in the closed position, blocking all coolant flow to the radiator.
• Replacing a stuck thermostat is a standard, relatively low-cost repair that prevents expensive engine damage from overheating.