EGR cooler. EGR SYSTEM. Right.3.0 LITER DIESEL. A heat exchanger that cools exhaust gases as they are recirculated back into the engine. A valve used to recirculate small amounts of exhaust back into the combustion chambers of the engine in order to decrease the combustion temperature, thereby reducing the formation of smog-producing nitrogen oxides. Includes Cooler Tube. Includes EGR Valve, Actuator, and Tube. Includes: EGR Valve. UNIT. Exhaust ().