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 42/100 to 81/100. 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) — 81/100 BUY
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 and thermostat, oil filter housing and valve cover leaks) are well-understood.
What to watch for: The electric water pump fails without warning, usually between 97.000–145.000 km. Replacement is €370–€740 and takes an afternoon. On 2009–2011 builds, also check that the VANOS-bolt recall was done — loose bolts can cut power or stall the engine. 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 (E46 325i / 330i, 2000–2006) — 86/100 BEST
The M54 was never fitted to the E90: the 325i and 330i launched in 2005 with the N52. If you want BMW's simpler older six, look at a late E46 instead. The M54's known faults are age-related and cheap — crankcase ventilation valve (and the oil consumption it causes), DISA valve, VANOS seals, cooling-system plastics and oil leaks — and well-kept engines run past 300.000 km.
The diesel question: M57 good, N47 risky
Diesel E90s outsold petrol versions in many European markets. The engine choice matters more than anywhere else in the range:
M57 (330d / 335d, 2005–2008) — 78/100 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) — 54/100 CAUTION
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 can snap. If it snaps, the engine is usually written off. Replacing the chain means removing the engine and costs €1.500–€4.000.
Every 318d and 320d from 2007–2012 uses the N47 (the 2005–2007 cars have the older M47). Chain wear is reported from around 100.000 km, and revised engines are not immune. Later N47s are also covered by BMW's EGR-cooler fire recall. The car shows few symptoms until the chain is far gone, so a rattle from the gearbox end of the engine is a reason to walk away.
The diesel rule for E90: six-cylinder diesel (M57, or N57 with the EGR-cooler recall checked) = good. Four-cylinder diesel (N47) = only with paperwork for a chain replacement and the recall.
The four-cylinder petrols: save money now, pay later
N42/N45/N46 (316i / 318i / 320i, 2005–2011) — 55/100 CAUTION
BMW's four-cylinders of this era are not the engine-killers their reputation suggests, but they are not cheap to keep either. The timing chain and its short original tensioner are the known weakness — budget €1,050–1,800 from around 100,000 km. The Valvetronic eccentric shaft and actuator (N42/N46, not the N45 in the 316i) and oil consumption from valve-stem seals and the crankcase breather complete the list. Examples past 250,000 km exist, but only with a full history.
The 316i and 318i are the cheapest E90s on the market. Buy one only with chain-service paperwork — or spend the same money on an N52 six.
Full N42/N45/N46 reliability report →
N43 (316i / 318i / 320i, 2007–2011) — 54/100 CAUTION
The direct-injection replacement for the N46 in some markets. It shares the N46's timing-chain weakness, which can do major engine damage, and adds a high-pressure fuel pump (€900–1.600), injectors and the NOx sensor of its lean-burn system. Oil leaks and oil use remain a topic. Not a car you want to own out of warranty without chain records.
The turbo sixes: exciting engines, expensive habits
N55 (335i, 2010–2013) — 79/100 BUY
The single-turbo successor to the N54, and a much more liveable daily driver. Known issues — valve cover gasket, VANOS solenoids, charge pipe, and on 2010–2011 cars the high-pressure fuel pump — 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) — 42/100 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. None of it destroys the engine, but it stacks up: one US specialist estimates $6,000–10,000 of deferred work on a neglected car.
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) — 52/100 CAUTION
The N53 is the direct-injection version of the N52, and it shares the N54's fault list minus the turbos: piezo injector failures, the high-pressure fuel pump, and the NOx sensor and NOx storage catalyst (up to about €3,000). Its lean-burn mode needs low-sulphur fuel, which is why it was sold only in Europe. None of these faults destroys the engine, but they add up. If you find a 325i from 2007+ with the N53 instead of the N52, buy it only with records showing late-index injectors and the fuel pump already done — otherwise 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 timing-chain gamble. 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 |
|---|---|---|---|
| Pre-E90 alternative | M54 325i/330i (E46) | 86/100 | Simpler older six — not sold in the E90 |
| Sweet spot | N52 325i (2006–2008) | 81/100 | Last NA six, silky, proven |
| Best diesel | M57 330d (2005–2008) | 78/100 | Torque monster, solid six |
| Enthusiast | N55 335i (2010–2013) | 79/100 | Fast, tuneable, liveable |
| Caution | N47 320d (2007–2012) | 54/100 | Rear timing chain can destroy the engine |
| Caution | N42/N45/N46 316i/318i | 55/100 | Timing chain, Valvetronic, oil use |