A defective thermostat can result in engine overheating and potential internal damage. Improve the reliability of your 6.7L primary cooling system with the Mishimoto Ford 6.7L Powerstroke High - Temperature Thermostat This thermostat is designed as a direct - fit replacement for your aged factory unit. The Mishimoto thermostat has higher activation temperatures (199 F206 F) compared to the factory thermostat (194 F201 F). The higher activation temperatures restrict coolant flow longer to allow a quicker engine warm - up, making this thermostat ideal for use in cold climates. Pair this thermostat set with the Mishimoto 6.7L Powerstroke Aluminum Primary Performance Radiator for a complete cooling system overhaul. As with all our products, this thermostat includes the Mishimoto Lifetime Warranty, ensuring superior product quality and craftsmanship.