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BMW B57 vs BMW M47: which engine is more reliable?

According to our risk index, the BMW B57 carries less risk than the BMW M47: 22/100 (low risk) versus 79/100 (very high risk). The BMW B57 has 3 documented serious faults, the main one being «EGR cooler leaks on the B57 (limited action on the 540d xDrive)»; the BMW M47 has 3 documented serious faults, the main one being «Intake swirl flap breakage (swirl flaps)».

Risk index

BMW B57

22

Low risk · 3 serious faults

Lower risk

Risk index

BMW M47

79

Very high risk · 3 serious faults

The index (0–100) weights the severity and frequency of the three most serious documented faults. How it is calculated

11 sourcesHow we work

Is the BMW B57 reliable?

The BMW B57 (2015 onwards) is the six-cylinder diesel that succeeded the N57. The sources consulted document no widespread faults: its most cited weak point is the AdBlue/SCR system, and it was left out of the big EGR campaigns that hit the N47 and N57. The timing chain is still at the back, next to the gearbox.[1][2]

See the 4 of the BMW B57 faults

Is the BMW M47 reliable?

The BMW M47 (1998-2007, a 4-cylinder diesel fitted to the 3 Series E46/E90, 1 Series E87, 5 Series E60, X3 E83, the Rover 75 and the Land Rover Freelander) is solid in its basic mechanicals, but the common rail versions, built since 2001, carry a serious and well-documented problem: the intake manifold swirl flaps can break and enter the cylinder, with a risk of engine damage. The turbo and injectors also account for known faults.[3][4][5][6]

See the 5 of the BMW M47 faults

Side-by-side comparison

Comparison of BMW B57 and BMW M47
BMW B57BMW M47
Technical data
TypeEngineEngine
FuelDieselDiesel
Displacement2,993 cm³1,995 cm³
TimingChainChain
Power265–400 hp116–163 hp
Productionsince 2015[7][8]1998–2007[3][4][9][10]
Reliability
Risk index (what is it?)22Low risk79Very high risk
Documented faults45
Of high or critical severity33
Worst severityHigh severityCritical severity
Main faults
  1. Medium severity: AdBlue/SCR system fault (NOx sensors, heater and pump)
  2. High severity: EGR cooler leaks on the B57 (limited action on the 540d xDrive)
  3. High severity: Timing chain wear on the gearbox side
  1. Critical severity: Intake swirl flap breakage (swirl flaps)
  2. High severity: Loss of power and turbo faults
  3. Medium severity: Blocked and seized injectors
Most expensive documented repairNo reliable dataNo reliable data
Which versions to buy
BuyRecommended versions
  • B57D30 265 hp, single turbo (B57D30O0, 2015-2020)[1]
  • B57D30 286-340 hp, twin turbo with 48 V (B57D30O2/T2, 2020 onwards)[1]
  • M47D20 116-136 hp (1998-2001)[3][5]
With cautionVersions to be cautious about
  • B57D30 320 hp, twin turbo (B57D30T0, 2015-2020)[1]
  • B57D30 400 hp, four turbos (B57D30S0, 2016-2020)[1]
  • M47D20TU 116-150 hp (2001-2004)[3][5][6]
  • M47D20TU2 122-163 hp (2004-2007)[3]
  • M47R 116-131 hp (Rover 75, MG ZT and Land Rover Freelander, 1998-2006)[3][11]
AvoidVersions to avoidNoneNone

Severity of each fault: green, low; amber, medium; red, high; dark red, critical. How we rate them

Cars that each one is fitted to

BMW B57

See the 8 models with the BMW B57

BMW M47

See the 7 models with the BMW M47

Other comparisons

With the BMW B57

With the BMW M47

Compare other engines

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Sources

Every fact on this page links to its source. If you find an error, let us know.

  1. Motor BMW B57: fiabilidad y averíasDasercars · Motoring press · consulted 4 October 2026 · in Spanish
  2. Motor BMW N57: diferencias con el B57Dasercars · Motoring press · consulted 4 October 2026 · in Spanish
  3. BMW M47Wikipedia (inglés) · Other source · consulted 27 September 2026
  4. BMW M47D20 engine specifications, problems and reliabilityBimmerPulse · Technical documentation · consulted 27 September 2026
  5. Motor BMW M47: problemas y averíasDasercars · Technical documentation · consulted 27 September 2026 · in Spanish
  6. BMW 3er E46: typische Probleme und SchwachstellenGebrauchtwagenberater · Technical documentation · consulted 27 September 2026 · in German
  7. BMW B57 (Wikipedia en)Wikipedia · Other source · consulted 4 October 2026
  8. BMW B57 (Wikipedia de)Wikipedia · Other source · consulted 4 October 2026 · in German
  9. BMW M47Wikipedia (alemán) · Other source · consulted 27 September 2026 · in German
  10. BMW 3 Series (E46)Wikipedia (inglés) · Other source · consulted 27 September 2026
  11. Rover 75Wikipedia (inglés) · Other source · consulted 27 September 2026