Description: O-Ring. 6 cylinder, with high output. 4.3L. 2nd Design. Dual Thermostat. Diesel. 2003-14. All models. 8 cylinder, 1993-97. 1/2, 3/4 & 1 ton, 1996 new style, 4.3, 5.0, 5.7L. Seals your vehicle's thermostat housing Helps prevent coolant from leaking from the engine This GM Genuine Part is designed, engineered, and tested to rigorous standards and is backed by General Motors