Mishimoto MMTS-E46-99 BMW M52, M54, M56 Engines Racing Thermostat Direct fit for All BMW E46 / any BMW vehicle with M52 / M54 / M56 Activates at lower temperature so coolant flows through system earlier Allows for cooler engine temperatures Mishimoto Activation: 158F (70C) / OEM Activation: 206.5F (97C) Mishimoto Lifetime Warranty