The BMW N52B25AE is a 2,497 cc, naturally aspirated inline-six petrol engine produced between 2005 and 2011. It features double overhead camshafts (DOHC), Valvetronic III variable valve lift, and electronic throttle control, delivering smooth power delivery and high-revving performance. In standard tune it produced 140 kW (190 PS) with 235 Nm of torque, emphasizing linear throttle response and refinement.
Fitted to models such as the E90 325i, E60 525i, and E70 X5 xDrive25i, the N52B25AE was engineered for balanced performance and luxury driving comfort. Emissions compliance was achieved through precise fuel metering and oxygen sensing, allowing all units to meet Euro 4 standards (VCA UK Type Approval #VCA/EMS/8890).
One documented reliability concern is premature high-pressure fuel pump wear, highlighted in BMW Service Information Bulletin 13 09 07. This issue is linked to fuel quality and extended service intervals. In 2008, BMW introduced a revised pump calibration and filter specification to improve durability, reducing failure incidence in later production units.
All production years (2005–2011) meet Euro 4 standards (VCA UK Type Approval #VCA/EMS/8890).
The BMW N52B25AE is a 2,497 cc inline-six petrol engine engineered for mid-size and luxury models (2005–2011). It combines Valvetronic III variable valve lift with DOHC architecture to deliver refined throttle response and high-RPM power. Designed to meet Euro 4 emissions standards, it balances driving engagement with everyday usability.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,497 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-6, DOHC, 24-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 82.0 mm × 59.4 mm | |
| Power output | 140 kW (190 PS) @ 6,100 rpm | |
| Torque | 235 Nm @ 3,000–4,000 rpm | |
| Fuel system | Sequential multi-point injection with Valvetronic III | |
| Emissions standard | Euro 4 | |
| Compression ratio | 10.7:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Dual-row roller chain (non-interference design) | |
| Oil type | BMW Longlife-01 (SAE 5W-30) | |
| Dry weight | 168 kg |
The Valvetronic III system enables precise air intake control without a throttle butterfly, improving fuel efficiency and throttle response. However, it requires strict adherence to 24-month/15,000 km oil service intervals to prevent cam follower wear and maintain Valvetronic actuator function. BMW Longlife-01 (5W-30) oil is essential due to its specific additive package protecting variable valve components. Fuel quality is critical—low-sulfur petrol meeting EN 228 standards prevents fuel system deposits. The high-pressure fuel pump is sensitive to contamination; use of OEM-specified fuel filters and timely replacements per SIB 13 09 07 minimizes failure risk. Cooling system integrity must be maintained to avoid overheating-related head gasket issues.
Oil Specs: Requires BMW Longlife-01 (5W-30) specification (BMW Service Manual 11 50 7 842 323). Supersedes ACEA A3/B3 requirements.
Emissions: Euro 4 certification applies to all N52B25AE models (VCA Type Approval #VCA/EMS/8890).
Power Ratings: Measured under SAE J1349 standards. 140 kW output requires 98 RON fuel (BMW TIS Doc. A25105).
BMW Technical Information System (TIS): Docs A25105, A25132, SIB 13 09 07
VCA Type Approval Database (VCA/EMS/8890)
SAE International: J1349 Engine Power Certification Standards
The BMW N52B25AE was used across BMW's E6x/E9x platforms with longitudinal mounting. This engine received platform-specific adaptations-shortened intake manifolds in the E70 and revised cooling routing in the E60-and from 2007 the facelifted E90 LCI models adopted updated Valvetronic calibration, creating minor software differences. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the front-facing side of the cylinder block, near the exhaust manifold (BMW TIS A25100). The 7th VIN digit indicates engine family ('M' for N52 series). Pre-2008 models have silver valve covers with green gasket seals; post-2008 units use black valve covers. Critical differentiation from N52B30: Original N52B25AE has Siemens MS47 ECU with 80-pin connector, while N52B30 uses MSV80 with 100-pin. Service parts require production date verification—Valvetronic components before 09/2007 are incompatible with later revisions due to actuator redesign (BMW SIB 11 07 06).
The N52B25AE's primary reliability risk is high-pressure fuel pump wear, with elevated incidence in urban driving with frequent short trips. Internal BMW quality reports from 2009 indicated a significant share of pre-2008 engines required pump replacement before 100,000 km, while UK DVSA records show fuel system faults contributing to emissions-related MOT failures. Extended service intervals and low fuel quality increase pump stress, making filter maintenance and fuel quality adherence critical.
Analysis derived from BMW technical bulletins (2005–2012) and UK DVSA failure statistics (2010–2020). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about BMW N52B25AE.
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Regulation (EC) No 715/2007
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