2012 BMW Serie 3 problems

• N47D20 116 hp (K0/K1, 2007-2014)

  116 hp · N47D20K0, N47D20K1

  It shares with the rest of the N47 family the rear timing chain defect; it is only advisable with a well-documented maintenance and timing history.^[2][4]

  With caution

• N47D20 143 hp (U0/U1, 2007-2014)

  143 hp · N47D20U0, N47D20U1

  Same timing chain risk as the rest of the range; it is worth verifying the timing history before buying.^[2][4]

  With caution

• N47D20 177-184 hp (O0/O1, 2007-2014)

  177–184 hp · N47D20O0, N47D20O1

  It is the most widely fitted N47D20 version (120d, 320d, 520d) and shares the same rear chain defect documented across the whole family.^[2][4]

  With caution

Faults that affect 2012 cars

• Critical severityFrequency: Very frequentTimingRear timing chain stretch and breakageYes: the N47 has its timing chain at the rear of the engine, next to the gearbox, and on a very high proportion of units, especially those built between 2007 and 2009, it stretches or breaks prematurely because of an inadequate tensioner, with a risk of destroying the engine.Repair (garage): €1,590–€3,000Appears at around 50,000 km
• Critical severityFrequency: CommonIntakeBroken intake manifold swirl flapsYes: the N47's intake manifold has plastic swirl flaps that, with diesel soot and the passing years, can crack, come loose and be sucked into the cylinder, with a risk of seriously damaging the piston, cylinder head and valves.
• High severityFrequency: CommonTurboTurbo and wastegate valve failureThe N47's turbo does not usually fail from general wear, but because of failure of the wastegate valve, which regulates boost and can seize or lose adjustment, sending fuel consumption soaring; oil leaks from the turbo itself are also common.Repair (garage): €900–€1,800
• Medium severityFrequency: CommonEmissions controlClogged or seized EGR valveYes, as on most diesels of its generation: the N47's EGR valve seizes or clogs with carbon, especially on cars used in town, causing an unstable idle, jerking and loss of power; it is not usually a serious fault if it is cleaned or replaced in time.Repair (garage): €400–€1,500
• Medium severityFrequency: CommonClutchDual-mass flywheel wear (manual gearbox versions)Yes: on manual-gearbox BMW N47s, the dual-mass flywheel can wear, especially after a lot of town mileage or driving in high gears at low revs; the typical symptoms are vibrations, a metallic rattle at idle and jerking when pulling away.Appears at around 150,000 km

• N57D30 204-211 hp, single turbo (U0/UL, 2010-2013)

  204–211 hp · N57D30U0, N57D30UL

  It shares with the rest of the N57 family the documented risk of the rear timing chain and, depending on the build date, may fall within the window covered by BMW's service campaign for the EGR cooler.^[7][8]

  With caution

• N57D30 245-258 hp, single turbo (O0/O1, 2008-2019)

  245–258 hp · N57D30O0, N57D30O1, N57D30OL

  The same documented rear timing chain risk and inclusion in the EGR cooler service campaign as the rest of the N57 range.^[7][8]

  With caution

Faults that affect 2012 cars

• Critical severityFrequency: Very frequentEmissions controlEGR cooler leaks with risk of engine fireYes: like the N47 and B47, the N57 is covered by BMW's service campaign for EGR cooler leaks, which can mix coolant with soot and oil to combustion temperatures. BMW checks free of charge the 6-cylinder engines built between July 2012 and June 2015 because of the fire risk.
• Critical severityFrequency: CommonTimingRear timing chain wearThe N57 inherits from the N47 the timing chain at the rear of the block, next to the gearbox, which complicates any repair. Unlike the N47, there is no documented campaign or wave of mass claims, and cases of serious wear appear mainly above 200,000 km.
• Medium severityFrequency: CommonOtherCrankshaft pulley vibration damper wearThe N57's crankshaft vibration damper (pulley) wears with use and, according to a technical guide to the engine, usually needs replacing between 80,000 and 120,000 km, giving warning with abnormal noises before failing completely.Appears at around 80,000 km

• N43B20 121-168 hp, 2.0 litres (2007-2013)

  121–168 hp · N43B20

  It accumulates all the documented risks of the family: wear of the timing chain, of the Valvetronic and of the VANOS and, because of its direct injection, failures of the injectors, ignition coils and NOx sensor.^[9][10]

  With caution

Faults that affect 2012 cars

• Critical severityFrequency: CommonTimingWear and breakage of the timing chain guidesYes: both the N43 and the N46 can stretch the timing chain and wear its plastic guides and tensioner. On the N43, English-language Wikipedia documents that a broken guide can release fragments that block the oil strainer and cause serious damage through lack of lubrication.
• Medium severityFrequency: CommonIntakeWear of the Valvetronic and the VANOS solenoid valvesOver the years, the eccentric shaft or the actuator motor of the Valvetronic can wear and cause heavy idle fluctuations; the VANOS solenoid valves also fail over time, with similar symptoms and a loss of power. According to English-language Wikipedia, the 1.6-litre N43B16 does not have Valvetronic.
• Medium severityFrequency: CommonLubricationOil leaks and consumption (rocker cover, vacuum pump and valve stem seals)Over the years, the rocker cover gasket and the brake servo vacuum pump gasket start to seep oil on the N43 and N46; on the N46 there are also the valve stem seals, which can cause more noticeable oil consumption than on the N43.

• N52B25 2.5 (2004-2015)

  174–215 hp · N52B25

  An engine considered very reliable for a BMW, but with known weak points (water pump, oil seals, valve cover) that are best seen to have been dealt with already.^[11][14]

  With caution

• N52B30 3.0 (2004-2015)

  215–268 hp · N52B30, N51B30

  Same weak points as the N52B25; units from before the end of 2008 may have noisy hydraulic lifters.^[11][14]

  With caution

• N53B30 3.0 (2007-2013)

  215–268 hp · N53B30

  The piezoelectric injectors and the high-pressure pump are the weak points identified by several sources; only recommended if their condition is verified.^[15][16][17]

  With caution

Faults that affect 2012 cars

• High severityFrequency: CommonInjectionN53 piezoelectric injector failureThe N53's piezoelectric direct injectors fail frequently and cause misfires, rough idle and limp mode; replacing them is expensive and they must be coded.
• Medium severityFrequency: CommonCoolingElectric water pump and thermostat failureThe N52's plastic electric water pump cracks or fails sooner than a mechanical one, and the thermostat usually goes with it; it is recommended to replace it as a precaution at around 80,000-100,000 km.Repair (garage): €350–€600Appears at around 80,000 km
• Medium severityFrequency: CommonLubricationOil leak from the oil filter housing gasketThe oil filter housing gasket hardens over time and leaks oil on all N52 engines; the leak can soil the engine and damage nearby parts.
• Low severityFrequency: CommonLubricationValve cover and crankcase ventilation valveThe N52's plastic valve cover cracks with heat cycles and the crankcase ventilation system fails, causing whistling, leaks and oil consumption.Repair (garage): €200–€350

• 2nd generation (6HP21/28/32, 2007-2014)

  · 6HP21, 6HP28, 6HP28X, 6HP32, 6HP32A

  The 2007 revision did not eliminate the family's weak points: jerking and mechatronic faults are still documented on cars with this version, and Jaguar ended up replacing the 6HP with the ZF 8HP on the XF as early as 2012. It is still worth checking the gearbox service history before buying.^[20][21][22]

  With caution

Faults that affect 2012 cars

• High severityFrequency: CommonElectronicsValve body and mechatronic failure: erratic shifts or a locked-up gearboxYes, and it can be serious: there are documented failures of the ZF 6HP valve body or mechatronic unit on BMW, Audi and Land Rover models from around 90,000-100,000 km, with cases that go as far as preventing a gear from engaging (including reverse) and dealer quotes of €6,000 to €10,000.Repair: €6,000–€10,000Appears at around 90,000 km
• Medium severityFrequency: CommonTransmissionJerking and harsh shifts from converter wear and ageing oilYes: on BMW, Audi and Land Rover models with the ZF 6HP there are reports of jerking, hesitation and harsh shifts from 80,000-150,000 km, especially if the gearbox oil has never been changed. The converter locks up in all six gears to save fuel, which speeds up its wear over the years.Repair (garage): €150–€400Appears at around 80,000 km
• Medium severityFrequency: OccasionalLubricationOil leaks from the sump or the gearbox sealsYes, although in a minority of cases: there are reports of ZF 6HP gearbox oil leaks on the BMW X5 (at 180,000 km) and the Audi A6 (between 204,000 and 208,000 km). If not repaired, the loss of pressure can speed up internal wear and lead to valve body or mechatronic failure.Repair (garage): €300–€600Appears at around 180,000 km

• High severityFrequency: CommonSteeringSteering rack and power steering pump failureIt is one of the faults owners cite most: fiches-auto.fr describes failures of the steering rack (sometimes locked) and of the power steering pump, mainly on the 318i and 320d, with steering columns replaced for €800-1,200 or a reprogramming for around €200-250 in France.
• Critical severityFrequency: OccasionalAirbags and safetyCampaigns over the Takata driver's airbag gas generatorsYes: the 3 Series E90/E91/E92/E93 is included in BMW's successive worldwide campaigns over the Takata driver's airbag gas generators, which can degrade over time and throw out metal fragments when deployed. The broadest, from May 2026, covers vehicles built between January 2006 and June 2015; an earlier one, from March 2024, had already covered older cars from 2004 and 2005.Repair: €0
• High severityFrequency: OccasionalClimate controlCampaign over fire risk from the heater fan connectorYes: in January 2021 BMW recalled around 430,000 3 Series E90/E91/E92/E93 cars in Germany (more than half a million worldwide) because the wiring connector of the heater fan regulator can corrode, cause a short circuit and set the vehicle on fire, even when parked. An earlier campaign, in autumn 2017, had already covered a first batch of cars in the United States.Repair: €0
• Medium severityFrequency: OccasionalSuspensionWear of shock absorbers, bushes and suspension bearingsWith mileage it is common for the E90 to need shock absorbers, bushes or suspension bearings: fiches-auto.fr places several cases between 150,000 and 170,000 km, and gebrauchtwagenberater.de cites German TÜV inspection data that flags springs and shock absorbers as a frequent point of attention.