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BMW B48 / B38 vs M270/M274: which engine is more reliable?

According to our risk index, the BMW B48 / B38 carries less risk than the M270/M274: 24/100 (low risk) versus 43/100 (moderate risk). The BMW B48 / B38 has 1 documented serious fault, the main one being «Timing chain on the early units (2014-2018), redesigned in the B48TU»; the M270/M274 has 1 documented serious fault, the main one being «Camshaft breakage due to a defective weld (2015 units)».

Risk index

BMW B48 / B38

24

Low risk · 1 serious fault

Lower risk

Risk index

M270/M274

43

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

10 sourcesHow we work

Is the BMW B48 / B38 reliable?

The BMW B48 (2.0 turbo, from 2014) and its three-cylinder sibling, the B38 (1.5), have a reputation as reliable engines within BMW's modern range: there is no serious, widespread fault on record, unlike the timing chain on the N47 diesel or the EGR fire risk on the B47. Keep an eye on the cooling circuit, the oil seals near the turbo and the VANOS, and the carbon build-up typical of direct injection; BMW revised the timing chain in 2018 (B48TU update).[1][2][3]

See the 4 of the BMW B48 / B38 faults

Is the M270/M274 reliable?

The M270 (transverse, front-wheel drive) and the M274 (longitudinal, rear-wheel drive) are the family of turbocharged, direct-injection 4-cylinder engines that Mercedes-Benz has fitted since 2011 in 1.6 and 2.0 litres. They are generally solid engines —the timing chain no longer gives trouble— but with documented faults: camshaft breakage caused by a defective weld (2015) and, on the M274, oil leaking from the camshaft adjuster into the connector.[4][5][6]

See the 5 of the M270/M274 faults

Side-by-side comparison

Comparison of BMW B48 / B38 and M270/M274
BMW B48 / B38M270/M274
Technical data
TypeEngineEngine
FuelPetrolPetrol
Displacement1,998 cm³1,991 cm³
TimingChainChain
Power136–312 hp102–245 hp
Productionsince 2014[1][7][8]since 2011[4][9]
Reliability
Risk index (what is it?)24Low risk43Moderate risk
Documented faults45
Of high or critical severity11
Worst severityHigh severityCritical severity
Main faults
  1. Medium severity: Deterioration of hoses and seals in the cooling circuit, with coolant loss
  2. Medium severity: Oil leaks or seepage from seals and covers, near the turbo and the VANOS
  3. High severity: Timing chain on the early units (2014-2018), redesigned in the B48TU
  1. Critical severity: Camshaft breakage due to a defective weld (2015 units)
  2. Medium severity: Oil leaking from the camshaft adjuster into the electrical connector (M274)
  3. Medium severity: Coolant leaks: thermostat and expansion tank
Most expensive documented repairNo reliable dataup to €500NOx sensor failure (code P2200) on the M274Published figure[5]
Which versions to buy
BuyRecommended versions
  • B38 1.5 136 hp (MINI Cooper, 118i)[2]
  • B48 2.0 178-197 hp (120i, 220i, 320i, 520i, X1/X2/X3 20i, MINI Cooper S)[2]
  • B48 2.0 252-258 hp (330i, 530i, X3/X4 xDrive30i)[2][10]
  • B48 2.0 up to 302-312 hp, high performance (MINI John Cooper Works, BMW X1 M35i)[2]
None
With cautionVersions to be cautious aboutNone
  • M270 1.6 turbo 102-156 hp[6]
  • M270 2.0 turbo 156-218 hp[6]
  • M274 2.0 turbo 156-245 hp[5][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 B48 / B38

See the 17 models with the BMW B48 / B38

M270/M274

See the 9 models with the M270/M274

Other comparisons

With the BMW B48 / B38

With the M270/M274

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 B48Wikipedia (inglés) · Other source · consulted 27 September 2026
  2. Motor BMW B48: defectos, mantenimiento y guía de compraRecambios y Accesorios BMW (blog) · Technical documentation · consulted 27 September 2026 · in Spanish
  3. BMW Reliability Has Changed, But the Internet Hasn't Caught UpBMWBLOG · Other source · published January 2026 · consulted 27 September 2026
  4. Mercedes-Benz M270 engineWikipedia · Other source · consulted 27 September 2026
  5. Mercedes M274: Typische Probleme & HaltbarkeitGebrauchtwagenberater · Motoring press · consulted 27 September 2026 · in German
  6. Mercedes M270: Typische Probleme & HaltbarkeitGebrauchtwagenberater · Motoring press · consulted 27 September 2026 · in German
  7. BMW B38Wikipedia (inglés) · Other source · consulted 27 September 2026
  8. BMW B48Wikipedia (alemán) · Other source · consulted 27 September 2026 · in German
  9. Mercedes-Benz Clase A (2012): información técnicakm77 · Technical documentation · consulted 27 September 2026 · in Spanish
  10. 5 BMWs That Prove the B48 Four-Cylinder Engine Is Better Than You ThinkBMWBLOG · Other source · published April 2026 · consulted 27 September 2026