The Mishimoto racing thermostat for the 05-11 Mercedes Benz G55 AMG will promote greater cooling efficiency in your stock or modified M113 5.4L Supercharged engine. Once the engine is fully warmed up, Mishimoto's G55 AMG 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 05-11 G55 AMG racing thermostat is the perfect addition to your street or track AMG and is a direct replacement for the factory thermostat. This thermostat includes the signature Mishimoto Lifetime Warranty.