Volkswagen EGR Cooler 21305-4BB1A

EGR Cooler (Exhaust Gas Recirculation Cooler) An EGR Cooler is a heat exchanger in diesel/gasoline engines that cools hot exhaust gases before recirculating them into the intake manifold. It lowers combustion temperatures, reduces NOx emissions, improves fuel efficiency, and protects engine components. Main materials • Heat exchange tubes/core: Ferritic stainless steel (high temperature & corrosion resistance) • Shell/body: Aluminum alloy or cast aluminum (lightweight, good thermal conductivity) • Seals & gaskets: High-temperature graphite or rubber Key functions • Cools exhaust gas (typically from 600–700°C to 150–250°C) • Reduces NOx formation • Improves combustion stability & fuel economy • Protects intake system from heat damage