2004 BMW Serie 1 problems

• M47D20TU2 122-163 hp (2004-2007)

  122–163 hp · M47D20TU2, M47TU2D20

  It carries the same swirl flap risk as the previous revision until BMW strengthened the design in 2006; check whether the manifold has already been inspected or reinforced.^[1]

  With caution

Faults that affect 2004 cars

• Critical severityFrequency: Very frequentIntakeIntake swirl flap breakage (swirl flaps)Yes: the common rail versions of the M47 (built since 2001) have flaps in the intake manifold that, with diesel soot and heat cycles, can break and be sucked into the cylinder, with a risk of serious damage to the piston, cylinder head and valves.
• High severityFrequency: CommonTurboLoss of power and turbo faultsThe M47's turbo does not usually fail suddenly, but it loses power gradually as carbon builds up in the variable geometry; the 150 hp variant built between September 2001 and November 2003 also accounts for turbo faults documented by specialist workshops.
• Medium severityFrequency: CommonInjectionBlocked and seized injectorsOver the miles, carbon builds up around the M47's injector seats and can seize them; a German used-car guide adds that the high-pressure pump on the first common rail units (before the first facelift) is relatively prone to failure.
• Medium severityFrequency: CommonClutchDual-mass flywheel wear (manual gearbox versions)On BMWs with the M47 engine and a manual gearbox, the dual-mass flywheel can wear with mileage, especially with a lot of urban use or long spells in high gears at low revs; typical symptoms are vibrations, a metallic rattle at idle and jerking when pulling away.Appears at around 150,000 km
• Critical severityFrequency: RareOtherOil leak from the brake vacuum pumpA BMW specialist workshop documents that the seals of the M47's vacuum pump, which generates the vacuum needed for brake assistance because a diesel does not produce it naturally, can wear and let oil through, which can end up stiffening the brake pedal.
• Low severityFrequency: OccasionalIntakeFaulty air flow meter on the BMW M47 (loss of power)On the 2.0 M47 diesel the air flow meter appears among parts that can fail with age and cause loss of power or judder. It is fixed by replacing the sensor; other causes must be ruled out first.Repair (garage): €100–€300

• N46B20 127-148 hp, indirect injection (2004-2007)

  127–148 hp · N46B20A, N46B20O1, N46B20U0, N46B20U1, N46B20U2

  Like the rest of the family, it can suffer wear of the timing chain guides and tensioner and of the Valvetronic or VANOS; as it has no direct injection, it is not affected by the injector and NOx sensor failures documented on the N43.^[3][4]

  With caution

Faults that affect 2004 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.^[5][7]

  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.^[5][7]

  With caution

Faults that affect 2004 cars

• 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: OccasionalLubricationN52 hydraulic lifter noiseN52 engines from before December 2008 can have hydraulic lifters that make a tapping noise when cold because of a lubrication problem.

• Critical severityFrequency: OccasionalAirbags and safetyRisk of driver's airbag inflator rupture (Takata)Yes: the 1 Series E87 is covered by BMW's European campaign for the Takata driver's airbag inflator, whose chemical propellant can degrade over time and, if the airbag deploys, throw out fragments that injure the occupants.
• Medium severityFrequency: CommonSuspensionBroken suspension springs and worn front-end bushesThe German TÜV Report, cited by gebrauchtwagenberater.de, notes that suspension springs on the E87 break fairly often; fiches-auto.fr adds front-end vibrations and worn bushes among owners' reports.Repair (garage): €400–€750
• High severityFrequency: RareBrakesABS/DSC module failurefiches-auto.fr documents a case of a faulty ABS/DSC unit on a 1 Series E87 at 75,000 km, with a repair cost of €2,100, which lights up the ABS and stability control warning lights.Repair (garage): €2,100