Thermostats play a vital role in engine management. Thermostats can fail in 2 possible manners; open or close position. If stuck open, the engine's heater will operate at reduced efficiency for an extended period of time or if stuck shut, will cause your car's engine to overheat leading to costly repairs or ultimately "complete engine failure". Aeroflow Performance offer a range of thermostats to suit a wide variety of makes and models, all featuring a lower opening temperature compared to their OEM counterparts. Reducing the temperature which an engine runs will make more power through better thermal and volumetric efficiency. These thermostats are a direct drop in with no modifications needed and a rubber seal is included in models that require this to seal.