BMW 320i e90 N43 engine
R28,000.00
The BMW N43 is a naturally aspirated inline four-cylinder petrol engine produced between 2007 and 2013. It replaced the N45 and N46 and was specifically designed for markets with low-sulfur fuel, which excluded it from North America. It was the first BMW four-cylinder to feature second-generation direct injection (High Precision Injection).
Technical Specifications
The engine features an aluminum block and head, dual overhead camshafts (DOHC), and 16 valves.
| Feature | Details |
|---|---|
| Displacement | 1.6L (N43B16) or 2.0L (N43B20) |
| Fuel System | High Precision Direct Injection with Piezo injectors |
| Valvetrain | Double-VANOS (variable valve timing) and Valvetronic (variable valve lift) |
| Combustion | Lean-burn technology with Stratified Charge mode |
| Output | 121 hp to 170 hp; 160 Nm to 210 Nm of torque |
Common Applications
The N43 was primarily used in European-market entry-level and mid-range models:
- 1 Series (E81, E82, E87, E88): 116i, 118i, 120i
- 3 Series (E90, E91, E92, E93): 316i, 318i, 320i
- 5 Series (E60, E61): 520i
Reliability & Known Issues
While innovative for efficiency (up to 23% more efficient than its predecessor), the N43 has a reputation for high maintenance needs as it ages:
- Fuel Injectors: The high-precision Piezo injectors are prone to failure, causing misfires and rough idling.
- NOx Sensor: Lean-burn technology requires an NOx sensor that frequently fails, triggering “limp mode” or high fuel consumption.
- Timing Chain Guides: Brittle plastic guides can break, potentially blocking the oil strainer and leading to oil starvation or engine seizure.
- Ignition Coils: Frequent failures lead to persistent misfire issues.
- Vacuum Pump: The camshaft-driven brake servo vacuum pump can fail, resulting in “heavy” brakes.
Note on Fuel: Because it utilizes a lean-burn system with an NOx catalytic converter, the N43 is highly sensitive to high-sulfur fuel, which can “poison” the exhaust treatment system.