The 3.0-liter inline-six BMW N51 (N51B30) was produced from 2007 to 2013 for American versions of the 128i (E82) and 328i (E90). It is essentially the N52KP adapted to the strict SULEV emission standards and produces 230-234 hp and 270 Nm.
N52 family: N52B25, N52B30, N51.
Specifications
| Production years | 2007-2013 |
| Displacement, cc | 2996 |
| Fuel system | distributed injection |
| Power output, hp | 230 – 234 |
| Torque output, Nm | 271 |
| Cylinder block | aluminum R6 |
| Block head | aluminum 24v |
| Cylinder bore, mm | 85.0 |
| Piston stroke, mm | 88.0 |
| Compression ratio | 10.0 |
| Hydraulic lifters | yes |
| Timing drive | chain |
| Phase regulator | double VANOS |
| Turbocharging | no |
| Recommended engine oil | 5W-30 |
| Engine oil capacity, liter | 7.0 |
| Fuel type | petrol |
| Euro standards | SULEV II |
| Fuel consumption, L/100 km (for BMW 328i 2009) — city — highway — combined |
13.1 8.4 11.2 |
| Engine lifespan, km | ~200 000 |
| Weight, kg | 162 |
The engine was installed on:
- BMW 1-Series E82 in 2008 – 2013;
- BMW 3-Series E90 in 2007 – 2013.
Disadvantages of the BMW N51 engine
- The engine is sensitive to fuel quality: it has Alusil cylinder walls instead of liners and no separate fuel filter, so scuffing is not rare;
- Oil consumption can be caused by a torn crankcase ventilation membrane or hardened valve stem seals;
- Poor oil and long change intervals wear the camshaft journals because of Valvetronic faults, and clogged Double VANOS filters are the main reason for their wear;
- The timing chain lasts over 200,000 km, but the plastic guides break much earlier, and their fragments can block the oil pickup;
- Oil leaks from the valve cover, vacuum pump gasket and oil filter housing are common, and the plastic DISA flaps can come off and fall into the cylinders.
Frequently asked questions about the BMW N51
How much power does the BMW N51 make?
The BMW N51 develops 230 - 234 hp and 271 Nm of torque.
How much oil does the BMW N51 take and which one?
Engine oil capacity: 7.0 liters. Recommended oil: 5W-30.
Does the BMW N51 have a timing belt or chain?
The BMW N51 uses a timing chain.
Is the BMW N51 turbocharged?
No, the BMW N51 is naturally aspirated.
Does the BMW N51 need valve clearance adjustment?
No, the BMW N51 has hydraulic lifters, so the valve clearances do not need to be adjusted.
How long does the BMW N51 last?
The typical lifespan of the BMW N51 is ~200 000 km with proper maintenance.
What is the fuel consumption of the BMW N51?
BMW 328i 2009: city 13.1, highway 8.4, combined 11.2 L/100 km.
What cars was the BMW N51 installed on?
BMW 1-Series E82 in 2008 - 2013; BMW 3-Series E90 in 2007 - 2013.
What are the common problems of the BMW N51?
The engine is sensitive to fuel quality: it has Alusil cylinder walls instead of liners and no separate fuel filter, so scuffing is not rare. Oil consumption can be caused by a torn crankcase ventilation membrane or hardened valve stem seals. All known problems.
