This replacement engine coolant thermostat housing is engineered to match the fit and durability of the stock thermostat housing on specified vehicles. It is designed to withstand extreme temperature changes to extend service life. Vehicle model years this part fits (be sure to check your vehicle trim using the Amazon garage) - [Chevrolet C4500 Kodiak: 2004, 2005, 2006, 2007] - [Chevrolet C5500 Kodiak: 2004, 2005, 2006, 2007] - [Chevrolet Silverado 2500 HD Classic: 2007] - [Chevrolet Silverado 2500 HD: 2004, 2005, 2006, 2007, 2008, 2009, 2010] - [Chevrolet Silverado 3500 Classic: 2007] - [Chevrolet Silverado 3500 HD: 2007, 2008, 2009, 2010] - [Chevrolet Silverado 3500: 2004, 2005, 2006] - [GMC C4500 Topkick: 2004, 2005, 2006, 2007] - [GMC C5500 Topkick: 2004, 2005, 2006, 2007] - [GMC Sierra 2500 HD Classic: 2007] - [GMC Sierra 2500 HD: 2004, 2005, 2006, 2007, 2008, 2009, 2010] - [GMC Sierra 3500 Classic: 2007] - [GMC Sierra 3500 HD: 2007, 2008, 2009, 2010] - [GMC Sierra 3500: 2004, 2005, 2006]