The E90 trap: cheap to buy, expensive to own — unless you know the engine code
The BMW E90 3 Series (2005–2013) is one of the most searched used cars in Europe. Prices start under €5.000 for high-mileage examples, which makes it look like a bargain. It isn't — not always.
BMW fitted over 10 different engines to the E90/E91/E92/E93 family, and their reliability scores on EngineScope range from 25/100 to 93/100. That's the difference between a car that runs to 300.000 km on basic maintenance and one that needs a €4.000 engine-out repair at 120.000 km.
The mileage on the odometer tells you how far the car has been driven. The engine code tells you whether it'll make it home.
The six-cylinder E90s: where the magic is
BMW's straight-six is the reason people buy the brand. In the E90, two naturally aspirated sixes stand out:
N52 (325i / 330i, 2005–2011) — 90/100 BEST
The N52 is the last naturally aspirated inline-six BMW ever made for the 3 Series. Magnesium-aluminium composite block, Valvetronic variable valve lift, and the kind of silky power delivery that made BMW's reputation. It's also remarkably tough — 250.000+ km is routine, and the known issues (electric water pump, valve cover gasket) are cheap and well-understood.
What to watch for: The electric water pump fails without warning, usually between 80.000–120.000 km. Replacement is €300–€500 and takes an afternoon. If the seller says it's been done, that's a good sign — it means they maintained the car properly.
The 325i (218 hp) is the sweet spot. The 330i (272 hp) is the same engine with different mapping — slightly more fun, slightly higher insurance. Both are excellent.
M54 (325i / 330i, pre-facelift 2004–2005) — 93/100 BEST
If you find a late E46 or very early E90 with the M54, buy it. This iron-block six is arguably BMW's most reliable engine ever. No magnesium block complexity, no electric water pump — just a beautifully over-engineered inline-six that refuses to break.
The M54 E90s are rare because BMW switched to the N52 quickly. A 2005 325i with the M54 and full service history is the sleeper pick of the entire E90 range.
The diesel question: M57 good, N47 disaster
Diesel E90s outsold petrol versions in many European markets. The engine choice here is binary:
M57 (330d / 335d, 2005–2008) — 84/100 BUY
The M57 3.0-litre six-cylinder diesel is a proper motorway engine. 231 hp, 520 Nm, and the kind of mid-range shove that makes overtaking effortless. Known issues are limited to swirl flaps and the occasional turbo actuator — annoying but not catastrophic. A well-maintained 330d will do 300.000 km.
N47 (318d / 320d, 2007–2012) — 35/100 AVOID
This is the single biggest trap in the used E90 market. The N47 2.0-litre four-cylinder diesel has a rear-mounted timing chain that stretches and eventually fails catastrophically. When it goes, the engine is destroyed. Replacement requires removing the engine and costs €2.000–€4.000.
Every 320d from 2007–2012 uses the N47. Every single one is at risk. The chain can fail as early as 80.000 km. There is no preventive fix short of replacing the chain assembly before it fails — and most owners don't, because the car shows no symptoms until it's too late.
The diesel rule for E90: six-cylinder diesel (M57/N57) = good. Four-cylinder diesel (N47) = walk away. No exceptions.
The four-cylinder petrols: save money now, pay later
N42/N45/N46 (316i / 318i / 320i, 2005–2011) — 28/100 AVOID
BMW's valvetronic four-cylinders looked good on paper — variable valve lift, decent fuel economy, adequate power. In practice, they consume oil chronically, the VANOS system fails, and the valvetronic eccentric shaft sensor is a recurring €500+ repair. These engines turn the E90 from a premium car into a maintenance project.
The 316i and 318i are the cheapest E90s on the market. There's a reason for that.
Full N42/N45/N46 reliability report →
N43 (320i, 2007–2011) — 48/100 CAUTION
The direct-injection replacement for the N46 in some markets. It solved the oil consumption but introduced lean-running issues, injector problems, and NOx sensor failures. An improvement over the N46, but still not a car you want to own out of warranty.
The turbo sixes: exciting engines, expensive habits
N55 (335i, 2010–2013) — 76/100 ACCEPTABLE
The single-turbo successor to the N54, and a much more liveable daily driver. Known issues — valve cover gasket, VANOS solenoids, charge pipe — are well-documented and relatively affordable. The N55 335i is the enthusiast's pick for a fast, tuneable E90 that won't bankrupt you.
N54 (335i, 2006–2010) — 32/100 AVOID
The N54 is a legend in the tuning community — twin-turbo, forged crank, responds beautifully to modifications. It's also a reliability disaster for daily driving: high-pressure fuel pump failure, injector failure, wastegate rattle, oil leaks from every gasket, and water pump failure. Budget €2.000–€3.000 per year in maintenance if you drive it daily.
Buy an N54 only if you're building a track car and accept the maintenance as part of the project.
N53 (325i / 330i, 2007–2011) — 25/100 AVOID
The N53 is the direct-injection version of the N52, and one of BMW's worst engines. Chronic lean-running codes, injector failures, and a design that doesn't tolerate European fuel quality variations. It was primarily sold in tax-advantaged European markets. If you find a 325i from 2007+ with the N53 instead of the N52, keep looking.
The rule for buying an E90
Buy a six-cylinder E90 or don't buy an E90 at all.
The four-cylinder petrols are money pits. The four-cylinder diesel is a ticking time bomb. The only four-cylinder worth considering is the N43 320i if you find one with documented maintenance and a low price — and even then, you're settling.
The sweet spot: a 2006–2008 325i with the N52, full service history, and the electric water pump already replaced. Depreciation is complete, the engine is proven, and parts are cheap. That's the E90 as BMW intended it.
| Pick | Engine | Score | Why |
|---|---|---|---|
| Dream | M54 325i/330i (2005) | 93/100 | Simplest, most reliable BMW six |
| Sweet spot | N52 325i (2006–2008) | 90/100 | Last NA six, silky, proven |
| Best diesel | M57 330d (2005–2008) | 84/100 | Torque monster, solid six |
| Enthusiast | N55 335i (2010–2013) | 76/100 | Fast, tuneable, liveable |
| Avoid | N47 320d (any year) | 35/100 | Timing chain will destroy engine |
| Avoid | N42/N45/N46 316i/318i | 28/100 | Chronic oil consumption |