BMW sDrive28i
BMW's first in-house four-cylinder turbo for the mid-size class. Timing chain and its guide rails are the main weakness — early replacement at any rattling noise.
N20 Turned Up to Eleven
245 hp with fat torque from 1,250 rpm — the metal roof stows in 20 seconds, and then it's a real roadster. The N20 punches well above its weight here.
Engine Weaknesses 7
The best-known weak point of the N20. The timing chain and oil pump chain stretch; the chain tensioner fails. BMW offered an extended warranty (7 years/100,000 km) for pre-2015 models.
Symptoms: Rattling on start, engine warning light, sudden power loss, in extreme cases engine damage
The electric water pump fails, risking overheating. A BMW-typical problem across all engines with electric coolant pumps since the N52 generation.
Symptoms: Overheating warning, temperature gauge rises quickly, coolant warning
On the N20 the oil pump sprocket can wear prematurely or the oil pump chain can break. In documented cases (50,000 km) an internal drive component failure caused complete oil pump failure — catastrophic engine damage.
Symptoms: Whistling noise that increases with rpm; oil pressure warning; metallic rushing from the engine bay; unusual vibrations
The N20 exhaust camshaft adjuster wears internally and causes intermittent fault codes (130308). Cleaning the solenoid valve alleviates the problem; replacing the adjuster resolves it permanently.
Symptoms: "Drive power not available" warning message; intermittent power loss; fault code 130308; rough running
The oil filter housing rubber gaskets harden and become porous — coolant and oil can mix. Since coolant is routed through the housing, engine damage is possible if repair is delayed.
Symptoms: Oil film in the coolant reservoir, discoloured oil filler cap (milky), oil in the coolant expansion tank, oil streaks on the engine block below the filter.
The wastegate control solenoid develops adaptive learning faults and boost pressure regulation errors (fault code 123401). BMW-workshop repair requires cam cover removal and special tools — approximately 6 labour hours according to BMW.
Symptoms: Engine warning light, increased turbo rattle, fault codes 123401/1234131 (wastegate solenoid, learning-cycle error), no noticeable power loss in early stages.
The N20B20 can develop above-average oil consumption at higher mileages. Caused by piston ring wear and valve stem seals — particularly with extended oil change intervals.
Symptoms: Regular oil consumption above 0.5 L / 1,000 km, occasional blue smoke on cold start or after prolonged idling.
Vehicle Weaknesses 7
The E89 folding hardtop can block after 8–13 years due to faulty micro-switches, broken wiring harnesses or leaking hydraulic lines. Hydraulic pump replacement up to €4,000.
The electromechanical power steering (EPS) on 2009–2012 model years can fail sporadically or permanently due to steering electronics faults. BMW carried out a goodwill action.
Porous door seals, blocked roof drains and leaking rear screen frames allow water into the footwell and boot. Early models are particularly susceptible.
Electronically controlled dampers (EDC) start leaking oil from around 120,000 km. OEM replacement up to €1,800 per unit. Bilstein B8/B12 are considered a recommended aftermarket alternative.
Older E89s show rust forming on engine longitudinal members and sills that works from the inside out. Road salt accelerates the process.
Leaking housing seals allow moisture into the tail lights. BMW replaced tail lights with a revised version in 2012. Facelift models are less affected.
The standard factory leather is comparatively thin and only surface-dyed. Seat cushions show significant wear from 80,000–100,000 km; backrests can develop abrasion.