2004.5-2005 GM 6.6L Duramax Updated EGR Cooler for the LLY. this EGR Cooler is quality-engineered to cool exhaust gas and recalculate it back to the engine. Replacement prevents coolant from leaking into the exhaust manifold and may protect the engine from extensive damage. Manufactured from high quality stainless steel. A rigorous quality inspections have been undertaken to ensure the EGR passes high product standards.