BMW 430i
Modular four-cylinder turbo, the workhorse of the current model range. Very broad power spectrum from 135 to 306 hp. Reliable; watch oil consumption and turbocharger at high mileage.
Coupe With Character
Reliable coupe with rear-wheel drive — the F33 cabriolet is especially appealing.
Engine Weaknesses 6
Timing chain guide rail can break; chain jump and engine damage follows. More common on early production years and with spirited driving.
Symptoms: Rattling, clattering from the engine, sudden power loss, engine damage
Oil filter housing with integrated oil/water heat exchanger leaks. Coolant loss and overheating risk from about 60,000 km.
Symptoms: Coolant level warning, oil puddle under engine, overheating
A plastic bleed line between the cylinder head and expansion tank becomes porous and breaks. Coolant loss follows; the mounting location is difficult to access, so labour costs dominate.
Symptoms: Dropping coolant level; coolant warning on the instrument cluster; faint sweet smell; no visible puddle under the car
The wastegate linkage on the B48 turbocharger has too much play by design and rattles, especially on cold start and at low revs. BMW offers a repair kit (e-actuator 11655A7A286) as a goodwill measure.
Symptoms: Metallic rattling or clattering from the turbo area on cold start and at idle; disappears at higher revs
As a direct-injection engine the B48 does not wash the intake valves with fuel. Oil vapour from crankcase ventilation and EGR gases form deposits that reduce flow and cause misfires.
Symptoms: Stumbling on cold start; power loss at high revs; rough idle; increased fuel consumption
The crankcase ventilation (PCV) integrated into the valve cover wears out and allows oil into the intake tract. Because PCV and valve cover are a single unit on the B48, the entire cover must be replaced.
Symptoms: Increased oil consumption (>0.5 L/1,000 km); blue smoke on cold start; oil in the intake line; rough idle
Vehicle Weaknesses 8
The four-cylinder N20 petrol engines (420i, 428i) suffer from premature timing chain stretch. Neglecting the issue risks engine damage.
The N47 diesel (418d, 420d up to March 2015) is notorious for timing chain failure. Chain snaps and causes engine damage.
On the F33 convertible, water enters through leaking roof edge seals.
In the F36 Gran Coupé, water enters the boot through faulty clips on the tailgate trim and damages the Harman Kardon amplifier.
The xDrive transfer case is sensitive to mixed tyres and infrequent oil changes.
The F33 convertible's hydraulic pump fails, typically from water ingress. The roof opens but won't close, or doesn't respond at all. BMW dealers charge around 2,300 € for pump replacement.
The A/C condenser is vulnerable to stone chips and loses refrigerant through small cracks.
The hardtop on the F33 doesn't permanently seal at the joints between the metal sections. Water tracks down to the A-pillar and enters the cabin.