The BMW M57 is a legendary inline-6 turbo diesel (1998–2005). Cast iron block, aluminium DOHC head, Common Rail injection, variable geometry turbo (later versions). 2.5 or 3.0 L, up to 204 hp (M57D30TU). Used in E39 530d, E46 330d, E53 X5. Huge torque and phenomenal reliability; easily exceeds 500,000 km with proper care. Main issues: turbo, glow plugs, intake swirl flaps. Many consider the M57 the best BMW diesel ever.
TU
In 2002, the M57 received a technical update (M57TU). Key changes: - Displacement increased to 3.0 L (2993 cc) via longer stroke. - New variable geometry turbocharger (VNT). - Second-generation Common Rail with 1600 bar injection pressure. - Bosch DDE 5.0 engine management. - Improved charge air cooling. Power increased to 204 hp, torque to 410 Nm.