The BMW N45 B16 A is a 1,596 cc, inline-four naturally aspirated petrol engine produced between 2004 and 2011. It features DOHC, 16-valve configuration, and BMW's Valvetronic II variable valve lift system, delivering 85 kW (116 PS) and 150 Nm of torque. Its precise throttle control and compact design provide a refined driving experience in entry-level models.
Fitted to the E81 1 Series and E87 1 Series, the N45 B16 A was engineered for fuel efficiency and urban drivability in compact applications. Emissions compliance was achieved through exhaust gas recirculation (EGR) and a three-way catalytic converter, enabling Euro 4 certification across all production years.
One documented concern is premature wear of the Valvetronic eccentric shaft sensor, which can lead to erratic idle and drivability issues. This issue, highlighted in BMW Service Information Bulletin 11 10 04, is often caused by carbon buildup and thermal stress on the potentiometer. In 2007, BMW introduced a revised sensor with improved sealing and wear resistance to enhance reliability.
All production years 2004–2011 meet Euro 4 emissions standards (VCA UK Type Approval #VCA/EMS/4568).
The BMW N45 B16 A is a 1,596 cc inline-four naturally aspirated petrol engine engineered for compact models (2004–2011). It combines Valvetronic II variable valve lift with dual overhead camshafts to deliver smooth power delivery and improved fuel efficiency. Designed to meet Euro 4 standards, it balances economy with everyday performance.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,596 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-4, DOHC, 16-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 78.0 mm × 83.5 mm | |
| Power output | 85 kW (116 PS) @ 6,000 rpm | |
| Torque | 150 Nm @ 4,250 rpm | |
| Fuel system | Bosch Motronic ME7.2 sequential port fuel injection | |
| Emissions standard | Euro 4 | |
| Compression ratio | 10.5:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Double-row timing chain | |
| Oil type | BMW Longlife-01 (SAE 5W-30) | |
| Dry weight | 152 kg |
The Valvetronic II system provides precise throttle control and improved fuel efficiency but requires adherence to 15,000 km oil change intervals to maintain chain longevity and sensor function. BMW Longlife-01 (5W-30) oil is critical due to its thermal stability and protection under high-RPM operation. Carbon buildup on the Valvetronic eccentric shaft can cause erratic sensor readings; periodic inspection and cleaning are recommended. The Motronic ME7.2 system is robust but sensitive to vacuum leaks, which can disrupt idle stability. Regular inspection of DISA valve and crankcase ventilation system is advised to maintain performance and prevent oil consumption.
Oil Specs: Requires BMW Longlife-01 (5W-30) specification (BMW SIB 11 03 04). Supersedes ACEA A3/B3 requirements.
Emissions: Euro 4 certification applies to all production years (2004–2011) (VCA Type Approval #VCA/EMS/4568).
Power Ratings: Measured under DIN 70020 standards. Output consistent across fuel qualities meeting EN 228.
BMW Technical Information System (TIS): Docs A28200, A28230, SIB 11 10 04
VCA Type Approval Database (VCA/EMS/4568)
DIN Deutsches Institut für Normung: DIN 70020 Engine Power Measurement
The BMW N45 B16 A was used across BMW's E81 and E87 platforms with transverse mounting. This engine received platform-specific adaptations-integrated Valvetronic on all units-and from 2007 the facelifted E81 LCI adopted the N46B16 variant with revised intake and updated engine management, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the right-side engine block near the exhaust manifold (BMW TIS A28290). The 7th VIN digit indicates engine family ('N' for N45 series). All N45 B16 A units have silver valve covers with "N45" and "Valvetronic" branding. Critical differentiation from N46B16: Original N45 B16 A uses Motronic ME7.2 ECU with Valvetronic II, while N46B16 features MS43 ECU with revised intake and no Valvetronic. Service parts require production date verification - Valvetronic sensors before 06/2007 are prone to failure and should be replaced with post-revision units per BMW SIB 11 10 04.
The N45 B16 A's primary reliability risk is Valvetronic eccentric shaft sensor failure, with elevated incidence in high-temperature operation. Internal BMW reports from 2005 indicated a significant number of pre-2007 units requiring sensor replacement before 120,000 km, while UK DVSA records show drivability-related failures were common in neglected examples. Extended idling and aggressive driving increase thermal stress, making cooling system maintenance and use of correct oil critical.
Analysis derived from BMW technical bulletins (2004–2011) and UK DVSA failure statistics (2012–2017). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about BMW N45B16A.
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