The Mishimoto racing thermostat for the 99-05 Volkwagen GTI 1.8T will promote greater cooling efficiency in your stock or modified GTI. Once the engine is fully warmed up, Mishimoto's Volkswagen GTI racing thermostat will open at a lower temperature than standard thermostats. This allows coolant to flow through the engine sooner, which reduces and maintains cooler engine temperatures. The Mishimoto 99-05 Volkwagen GTI 1.8T racing thermostat is the perfect addition to your street or track GTI and is a direct replacement for the stock thermostat. This thermostat includes the signature Mishimoto Lifetime Warranty.