120i N43
Lean-burn direct-injection four. Economical when healthy and expensive when not. The injectors and NOx sensors are the whole story.
Overview
The 120i is the N43 petrol version of the BMW 1 Series hatchback (E81), sold 2007–2011 with 170 PS and manual or automatic. Demands diligence at level 3. Piezo injectors and NOx sensors recur, and a full set is a meaningful share of the car's value. 18 failure modes are recorded against its engine, gearbox, chassis and shared components. Prices on this page are illustrative placeholders rather than a sourced market sample. See the methodology for how the bands are derived.
BMW 1 Series hatchback (E81) · photo BMW E81 116i Performance by Thomas doerfer · CC BY-SA 3.0 · Wikimedia Commons
Ranked by probability × repair cost. 18 recorded in total.
Risk level −22 · Likely spend vs price −26 · all issues →
Known issues, ranked by expected cost
Faults recorded against this engine, its components and its chassis, ranked by likelihood × repair cost. Costs are indicative ranges with a stated labour basis.
Ranked by probability × repair cost, not by how loudly a failure is discussed. Inherited from the engine, gearbox, chassis and shared components, each written once. All 18 issues in full →
Pre-purchase inspection
The same issue records, reordered into the sequence you can actually check them in: cold start, static, drive, paperwork.
1Cold startYou get one. If the engine is warm when you arrive, come back another day.
2Static checksEngine off, ideally on a lift.
3On the driveInclude low-speed manoeuvring, not just an open road.
4PaperworkOn these cars the folder is most of the value.
5OBD scanMandatory. A seller who refuses a scan has answered the question.
Mileage and servicing
What the odometer does and doesn't tell you here, plus the service items whose neglect causes the expensive failures above.
Buy on a clean injector scan, not on mileage. History of injector work is worth paying for.
| Service item | Interval | Cost |
|---|---|---|
| Engine oil Injection longevity follows oil quality | 12,000–15,000 km | €90–150 |
| Injector/NOx scan The honest read on the fuel system | on purchase | free |
What to pay
What this engine sells for, against the median of every engine in the chassis. All figures are illustrative placeholders. See the basis chips.
Enter an asking price to get a verdict against this variant's band: cheap, fair, good buy or overpriced.
United States vs Europe
1 EUR = 1.08 USD ·US figures are the EU band converted at a stated rate. No US market differential is modelled: we hold no sourced US asking prices, and inventing one would be worse than saying so. What the comparison does show for real is availability. Most of this range was never sold in the US.
- ModelBMW 1 Series 120i
- ChassisE81
- EngineN43
- Years2007–2011
- MarketCentral EU
- Windowrolling 12 months to 2026-07
Good buy isn't the same as cheapest. The good-buy figure assumes the known failure items are either done with receipts or verifiably not yet due. Full breakdown by facelift phase →
Buyer notes
Our judgement, kept separate from the records it's built on.
Everything above this line comes from the issue and specification records. This paragraph is our judgement on top of them. See how we reach it.
Full specification
Manufacturer figures for this engine and body, as recorded in the variant and engine data.
| Engine code | N43B20 |
| Configuration | I4, naturally aspirated, lean-burn · 1995 cc |
| Fuel / injection | petrol · direct |
| Model years | 2007–2011 |
| Facelift phase | Pre-facelift only, to -1 |
| Power / torque | 170 PS · 210 Nm |
| Transmissions | 6-speed manual · 6-speed automatic (ZF) |
| Gearbox families | Getrag six-speed manual · ZF 6HP19 / 6HP21 six-speed automatic |
| Drivetrain | RWD |
| Economy (real-world) | 6.5–8.5 l/100 km mixed |
| Markets | EU |