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BMW B38 / B37 vs BMW B58: which engine is more reliable?

According to our risk index, the BMW B38 / B37 carries less risk than the BMW B58: 20/100 (low risk) versus 38/100 (moderate risk). The BMW B38 / B37 has 1 documented serious fault, the main one being «B38 crankshaft thrust bearing failure (units before April 2015)»; the BMW B58 has 1 documented serious fault, the main one being «Failure of the oil pump with a plastic rotor housing».

Risk index

BMW B38 / B37

20

Low risk · 1 serious fault

Lower risk

Risk index

BMW B58

38

Moderate risk · 1 serious fault

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

16 sourcesHow we work

Is the BMW B38 / B37 reliable?

BMW and MINI's three-cylinder B38 (petrol) and B37 (diesel) have no serious, widespread documented fault. The only problem reported in the press is the crankshaft thrust bearing on early B38 units (up to April 2015), corrected by BMW. BMW's EGR campaigns affect four- and six-cylinder diesels, not the B37.[1][2][3]

See the 3 of the BMW B38 / B37 faults

Is the BMW B58 reliable?

The B58 (3.0 turbo straight-six, since 2015) is considered robust and less troublesome than the N54/N55 it replaced, and the sources do not document widespread internal failures. The known faults are on the periphery: the plastic oil filter housing, crankcase ventilation, gaskets and coolant. On units built before 2021 there are also US reports of an oil pump with a plastic housing.[4][5][6][7]

See the 6 of the BMW B58 faults

Side-by-side comparison

Comparison of BMW B38 / B37 and BMW B58
BMW B38 / B37BMW B58
Technical data
TypeEngineEngine
FuelPetrolPetrol
Displacement1,499 cm³2,998 cm³
TimingChainChain
Power75–231 hp290–441 hp
Productionsince 2014[8][9][10]since 2015[11][12]
Reliability
Risk index (what is it?)20Low risk38Moderate risk
Documented faults36
Of high or critical severity11
Worst severityCritical severityHigh severity
Main faults
  1. Critical severity: B38 crankshaft thrust bearing failure (units before April 2015)
  2. Medium severity: Coolant leaks and water pump or thermostat failure on the B38
  3. Low severity: Carbon build-up on the B38's intake valves and injectors
  1. High severity: Failure of the oil pump with a plastic rotor housing
  2. Medium severity: Oil and coolant leak from the plastic oil filter housing
  3. Medium severity: Failure of the crankcase ventilation PCV valve (integrated in the valve cover)
Most expensive documented repairNo reliable dataNo reliable data
Which versions to buy
BuyRecommended versions
  • B38 1.5 136-140 hp from April 2015 (B38A15 / B38B15)[1]
  • B37 1.5 diesel 95-116 hp (B37C15K0 / B37C15U0), up to 2017[13]
  • B37TÜ1 1.5 diesel 95-116 hp (from late 2017)[14]
  • B58TU2 381 hp (B58B30M2, since 2022)[5][6]
With cautionVersions to be cautious about
  • B38 1.2 (B38A12, MINI One)[9]
  • B38 1.5 136 hp up to April 2015 (B38A15)[1]
  • B38K15T0 231 hp (BMW i8)[15]
  • B58 326 hp (B58B30M0, 2015-2019)[5][6][16]
  • B58 340-360 hp (B58B30M0, 2016-2019)[5][6][16]
  • B58TU 333-340 hp (B58B30M1, since 2018)[5][6]
  • B58TU 374 hp (B58B30O1, M340i, M440i and M240i, since 2019)[6]
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 B38 / B37

See the 16 models with the BMW B38 / B37

BMW B58

See the 16 models with the BMW B58

Other comparisons

With the BMW B38 / B37

With the BMW B58

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. BMW Dreizylinder: Dauertest-Probleme des B38 behoben?BimmerToday · Motoring press · published 5 October 2017 · consulted 4 October 2026 · in German
  2. 2024: BMW recall due to EGR coolers extended againcar-recalls.eu · Motoring press · published 28 March 2024 · consulted 4 October 2026
  3. BMW diésel Europa: llamada a revisión por el EGR y riesgo de incendioDiariomotor · Motoring press · consulted 4 October 2026 · in Spanish
  4. The 5 Most Common BMW B58 Engine ProblemsBMW Tuning · Technical documentation · published 7 February 2020 · consulted 9 October 2026
  5. BMW B58 EngineFCP Euro · Technical documentation · consulted 9 October 2026
  6. The Popular BMW B58 Inline-Six Engine Has One Big Achilles HeelThe Autopian · Motoring press · published 14 June 2024 · consulted 9 October 2026
  7. ¿En qué se diferencian los motores B58 y S58 de BMW?Diariomotor · Motoring press · published 27 April 2024 · consulted 9 October 2026 · in Spanish
  8. BMW B38 (Wikipedia)Wikipedia · Other source · consulted 4 October 2026
  9. BMW B38 (Wikipedia, alemán)Wikipedia · Other source · consulted 4 October 2026 · in German
  10. BMW B37 (Wikipedia)Wikipedia · Other source · consulted 4 October 2026
  11. BMW B58Wikipedia (inglés) · Other source · consulted 9 October 2026
  12. BMW B58Wikipedia (alemán) · Other source · consulted 9 October 2026 · in German
  13. Project one M: MINI Cooper D F56 fährt eine Million Kilometer in 12 JahrenBimmerToday · Motoring press · published 24 June 2026 · consulted 4 October 2026 · in German
  14. BMW Baukasten-Diesel: Mehr Infos zur TÜ1 für B47 und B37BimmerToday · Motoring press · published 20 November 2017 · consulted 4 October 2026 · in German
  15. BMW i8 (Wikipedia)Wikipedia · Other source · consulted 4 October 2026
  16. How A Plastic Part On BMW's B58 Engine Can Turn An Oil Change Into A $3,000 RepairThe Autopian · Motoring press · published 28 March 2025 · consulted 9 October 2026