Mishimoto MMTS-CHV-01DL Chevrolet/GMC 6.6L Duramax Engine Low Temperature Thermostats (Set of 2) Fits 20012013 Chevrolet/GMC 6.6L Duramax Activates at lower temperature so coolant flows through system earlier Allows for cooler engine temperatures Purchase Includes: One 174 F Thermostat / One 180 F Thermostat Mishimoto Lifetime Warranty Activate at a lower temperature than the OEM thermostats Perfect for Duramax owners who live in warmer climates, or use their trucks under heavy load or strenuous driving conditions Allow for cooler temperatures