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BMW B48 / B38 vs BMW N20: which engine is more reliable?

According to our risk index, the BMW B48 / B38 carries less risk than the BMW N20: 24/100 (low risk) versus 63/100 (high 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 BMW N20 has 2 documented serious faults, the main one being «Timing chain guide and tensioner wear (2011-2015)».

Risk index

BMW B48 / B38

24

Low risk · 1 serious fault

Lower risk

Risk index

BMW N20

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

9 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 BMW N20 reliable?

The BMW N20 (2011-2017) was the first turbocharged four-cylinder with which BMW replaced its naturally aspirated six-cylinders in models such as the 320i, 328i and X3, and it is generally mechanically sound. Its best-documented weak point is the timing chain guides and tensioner on units built before 2015; oil leaks, the electric water pump and, to a lesser extent, the turbo and the high-pressure fuel pump are also known issues.[4][5]

See the 5 of the BMW N20 faults

Side-by-side comparison

Comparison of BMW B48 / B38 and BMW N20
BMW B48 / B38BMW N20
Technical data
TypeEngineEngine
FuelPetrolPetrol
Displacement1,998 cm³1,997 cm³
TimingChainChain
Power136–312 hp156–245 hp
Productionsince 2014[1][6][7]2011–2017[4][8]
Reliability
Risk index (what is it?)24Low risk63High risk
Documented faults45
Of high or critical severity12
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: Timing chain guide and tensioner wear (2011-2015)
  2. Critical severity: Electric water pump failure (BMW campaign in the US over fire risk)
  3. Medium severity: Oil leaks from the rocker cover gasket and the filter housing
Most expensive documented repairNo reliable dataNo reliable data
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][9]
  • 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
  • N20B20 156 hp (115 kW, 2013-2016)[5]
  • N20B20B 184 hp (135 kW, 2011-2017)[5]
  • N20B20 218 hp (160 kW, 2012-2015)[5]
  • N20B20A 245 hp (180 kW, 2011-2017)[5]
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

BMW N20

See the 8 models with the BMW N20

Other comparisons

With the BMW B48 / B38

With the BMW N20

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. BMW N20Wikipedia (inglés) · Other source · consulted 27 September 2026
  5. BMW N20 Engine: Pros, Cons, Reliability, Tuning, and Maintenance GuideBMW BLOG · Motoring press · published 8 June 2025 · consulted 27 September 2026
  6. BMW B38Wikipedia (inglés) · Other source · consulted 27 September 2026
  7. BMW B48Wikipedia (alemán) · Other source · consulted 27 September 2026 · in German
  8. BMW N20Wikipedia (alemán) · Other source · consulted 27 September 2026 · in German
  9. 5 BMWs That Prove the B48 Four-Cylinder Engine Is Better Than You ThinkBMWBLOG · Other source · published April 2026 · consulted 27 September 2026