What these engines share
BMW's mainstream four-cylinder turbo petrols: the N20 (2011–2015) and B48 (2014–present). Both are 2.0-litre turbocharged units powering the 3 Series (320i/328i/330i) and X1/X3. The B48's modular architecture was designed from scratch — it's not a revision of the N20.
B48 vs N20 at a glance
| B48 | N20 | |
|---|---|---|
| Brand | BMW | BMW |
| Score | 82/100 | 58/100 |
| Verdict | BUY | CAUTION |
| Type | 2.0L Turbo I4 | 2.0L Turbo I4 |
| Known issues | 3 | 3 |
B48 — 82/100 (BUY)
Found in: 1 Series, 2 Series, 2 Series Active Tourer, 3 Series, 320i, 320i GT, 330i, 330i GT
Key issues
- Intake valve carbon buildup (DI) — severity minor, cost €600, onset 60.000 km
- Oil filter housing gasket — early units (2014-2016) — severity moderate, cost €500, onset 40.000 km
- Coolant vent line failure — severity moderate, cost €250, onset 40.000 km
N20 — 58/100 (CAUTION)
Found in: 1 Series, 2 Series, 3 Series, 320i, 328i, 4 Series, 428i, 5 Series
Key issues
- Timing chain + guide + tensioner — class-action — severity critical, cost €2.800, onset 60.000 km
- Electric water pump failure — severity high, cost €800, onset 80.000 km
- Oil filter housing gasket leak — severity moderate, cost €500, onset 60.000 km
Verdict: B48 wins by 24 points
The B48 scores 82/100 vs the N20's 58/100 — a 24-point difference. This is a significant gap. The B48 is clearly the safer choice.
Which one should you buy?
The B48 is the clearly safer choice. The N20's timing chain tensioner issues are well-documented and can lead to catastrophic failure. If buying a 320i or 328i, make sure it's a 2016 or later model with the B48. The price difference is worth it.
Generated from EngineScope's reliability database. Reviewed by the editorial team. Methodology →