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BMW B57 vs BMW M57: which engine is more reliable?

According to our risk index, the BMW B57 carries less risk than the BMW M57: 22/100 (low risk) versus 63/100 (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 M57 has 2 documented serious faults, the main one being «Broken intake swirl flaps».

Risk index

BMW B57

22

Low risk · 3 serious faults

Lower risk

Risk index

BMW M57

63

High risk · 2 serious faults

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

8 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 M57 reliable?

The BMW M57 (1998-2010) is a six-cylinder diesel with a reputation for great mechanical longevity, capable of exceeding 500,000 km when well maintained, but a good share of the versions built before 2008 -especially with an automatic gearbox- have metal swirl flaps in the intake that can break and wreck the engine; check whether the car has them and what condition they are in before buying.[3][4][5]

See the 4 of the BMW M57 faults

Side-by-side comparison

Comparison of BMW B57 and BMW M57
BMW B57BMW M57
Technical data
TypeEngineEngine
FuelDieselDiesel
Displacement2,993 cm³—
TimingChainChain
Power265–400 hp150–286 hp
Productionsince 2015[6][7]1998–2010[3][8]
Reliability
Risk index (what is it?)22Low risk63High risk
Documented faults44
Of high or critical severity32
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: Broken intake swirl flaps
  2. High severity: Crankcase ventilation (PCV) valve failure
  3. Medium severity: Cracked exhaust manifold
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]
None
With cautionVersions to be cautious about
  • B57D30 320 hp, twin turbo (B57D30T0, 2015-2020)[1]
  • B57D30 400 hp, four turbos (B57D30S0, 2016-2020)[1]
  • M57D25, 2.5 litres (150-197 hp, 2000-2010 depending on application)[4]
  • M57D30, first-generation 3.0 litres (177-193 hp, 1998-2006 depending on application)[4]
  • M57D30TU, first revision 3.0 litres (201-272 hp, 2001-2006)[4]
  • M57D30TU2, second revision 3.0 litres, aluminium block (204-286 hp, 2004-2010)[4]
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 M57

See the 10 models with the BMW M57

Other comparisons

With the BMW B57

With the BMW M57

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 M57Wikipedia (inglés) · Other source · consulted 27 September 2026
  4. Motor BMW M57 - Reparación EspecializadaDasercars · Technical documentation · consulted 27 September 2026 · in Spanish
  5. BMW M57D30 engine specifications, problems and reliabilityBimmerPulse · Technical documentation · consulted 27 September 2026
  6. BMW B57 (Wikipedia en)Wikipedia · Other source · consulted 4 October 2026
  7. BMW B57 (Wikipedia de)Wikipedia · Other source · consulted 4 October 2026 · in German
  8. BMW M57Wikipedia (alemán) · Other source · consulted 27 September 2026 · in German