The exhaust system consists of two front exhaust pipes, which on the 520i, 523i and 525tds models are combined in front of the catalytic converter. This is followed by the middle and subsequent mufflers. On the 528i, the exhaust system in the area of the catalytic converter and exhaust pipe consists of two branches. On a gasoline engine, one oxygen sensor is screwed into each front exhaust port to control the catalytic converter.
Front exhaust pipe bolted to manifold outlet (Gas engine) or with turbocharger (turbocharged diesel engine). All parts of the exhaust system can be replaced separately during repairs.