The BMW M57 D25 (256D2) is a 2,497 cc, inline-six turbo-diesel engine produced between 2001 and 2004. It forms part of BMW's second-generation modular diesel engine family, featuring dual overhead camshafts (DOHC), four valves per cylinder, and a single variable geometry turbocharger (VGT). With a peak output of 105 kW (143 PS) and 330 Nm of torque, it delivers strong low-end pulling power ideal for executive sedans and touring vehicles.
Fitted to the E46 3 Series (325d), E39 5 Series (525d), and E53 X5 (X5 2.5d), the M57 D25 was engineered for balanced performance, fuel efficiency, and driver engagement. It utilises Bosch EDC16 engine management with common rail direct injection (up to 1,600 bar) and features a diesel particulate filter (DPF) in certain markets, enabling compliance with Euro 3 emissions standards.
One documented service concern involves high-pressure fuel pump (HPFP) failures observed in early production units, particularly in engines built before mid-2003. This issue, referenced in BMW Service Information Bulletin 13 05 03, was attributed to inadequate lubrication film stability under extended service intervals. BMW addressed this through revised pump internals and updated oil specification requirements, transitioning to higher-detergent oils compliant with BMW Longlife-02.
Production years 2001–2003 meet Euro 3 standards; 2004 models comply with Euro 4 (VCA UK Type Approval #VCA/EMS/5680).
The BMW M57 D25 (256D2) is a 2,497 cc inline-six turbo-diesel engineered for compact and grand tourer applications (2001–2004). It combines DOHC valvetrain architecture with Bosch common rail injection and a single VGT to deliver responsive throttle characteristics and high-RPM power. Designed to meet Euro 3 and later Euro 4 standards, it balances sporty performance with daily drivability.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,497 cc | |
| Fuel type | Diesel | |
| Configuration | Inline-6, DOHC, 24-valve | |
| Aspiration | Turbocharged | |
| Bore × stroke | 84.0 mm × 75.0 mm | |
| Power output | 105 kW (143 PS) @ 4,000 rpm | |
| Torque | 330 Nm @ 2,000–2,500 rpm | |
| Fuel system | Bosch CRS 2.0 common-rail (up to 1,600 bar) | |
| Emissions standard | Euro 3 (2001–2003); Euro 4 (2004) | |
| Compression ratio | 17.5:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Single variable-geometry turbo (Garrett GT1749V) | |
| Timing system | Double-row roller chain (non-interference design) | |
| Oil type | BMW Longlife-02 (SAE 5W-30 or 10W-40) | |
| Dry weight | 202 kg |
The naturally aspirated inline-six layout provides smooth, linear power delivery ideal for spirited driving but demands consistent maintenance to preserve longevity. BMW Longlife-02 (5W-30 or 10W-40) oil is critical due to its thermal stability and anti-wear additives protecting the HPFP and turbocharger. Early M57 D25 engines are prone to fuel pump failure if incorrect oil is used or service intervals exceed 15,000 km. The single VGT improves mid-range torque but may develop actuator clogging or vacuum leaks over time, requiring periodic cleaning or replacement. Coolant system integrity is essential—aluminium construction and rubber hoses degrade if coolant is not replaced every 2–3 years per BMW TIS A25702.
Oil Specs: Requires BMW Longlife-02 specification (BMW SIB 13 05 03). Replaces earlier BMW 502.00 standard.
Emissions: Euro 3 certification applies to pre-2004 models only (VCA Type Approval #VCA/EMS/5680). Euro 4 compliance confirmed for 2004 production.
Power Ratings: Measured under DIN 70020 standards. Output consistent across all markets without fuel quality dependency.
BMW Technical Information System (TIS): Docs A25702, A25914, SIB 13 05 03
VCA Type Approval Database (VCA/EMS/5680)
SAE International: J2723 Engine Power Test Code
The BMW M57 D25 (256D2) was used across BMW's E46, E39, and E53 platforms with longitudinal mounting. This engine received platform-specific adaptations-integrated air intake routing in the E46 sedan and compact exhaust manifold in the X5-and from 2003 the updated E46 LCI models adopted revised ECU calibration and ignition coils, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the right-side cylinder head near the exhaust manifold (BMW TIS A25807). The 7th VIN digit indicates engine family ('M' for M57 series). Pre-2003 models have silver valve covers with round ignition coils; post-2003 LCI units use black valve covers with integrated coil packs. Critical differentiation from M57TU: Original M57 D25 uses Bosch EDC16 ECU with separate coil drivers, while M57TU (2004+) uses Siemens MSV70 with direct ignition control. Service parts require production date verification—fuel pumps before 06/2003 are not interchangeable with later units due to internal revisions (BMW SIB 13 05 03).
The M57 D25's primary reliability risk is high-pressure fuel pump failure in early builds, with elevated incidence in high-mileage or poorly maintained vehicles. Internal BMW quality reports from 2003 indicated a significant portion of pre-LCI engines showing pump degradation before 150,000 km, while UK DVSA MOT data links a notable share of emissions failures to aging EGR units in city-driven examples. Extended oil intervals and low-quality lubricants increase wear rates, making correct oil specification and timely servicing critical.
Analysis derived from BMW technical bulletins (2001-2005) and UK DVSA failure statistics (2004-2008). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about BMW M57D25-256D2.
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