The Mishimoto 15-17 Volkswagen Golf Racing Thermostat is a high-performance thermostat that is designed to provide optimal cooling efficiency in your VW Golf. This thermostat has a 73°C opening temperature, which is significantly lower than OEM thermostats, allowing your coolant to flow through the engine faster and at a lower temperature. This thermostat is constructed with a high-quality brass housing and a stainless steel piston actuator for maximum durability, and it is backed by Mishimoto's lifetime warranty.