Thermostats allow a vehicle's engine to maintain proper temperature. While an engine must be cooled to prevent its self destruction, it also needs to reach operating temperature as quickly as possible. Since metal expands under heat and fuel combustion, as well as exhaust functions, happen differently at higher temperatures the engine is designed to operate best at this temperature. The thermostat holds coolant inside the engine block while the engine heats up, then springs open once a certain temperature is reached to begin circulation and prevent overheating.
Thermostats can fail, basically in one of two ways; either stuck open or stuck closed. When a thermostat is stuck open, the engine will take much longer than it should reaching its operating temperature. This will cause poor fuel economy and emissions, as well as prevent the heater core from warming air as quickly as it could. When a thermostat is stuck closed, the coolant inside the engine can't escape to the radiator and the engine will quickly overheat.
Replacing thermostats will vary from vehicle to vehicle depending on its exact location and the amount of space available to work with.
We stock and sell a wide variety of quality thermostats from these manufacturers: