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1.6 CRDi vs BMW B57: which engine is more reliable?

According to our risk index, the BMW B57 carries less risk than the 1.6 CRDi: 22/100 (low risk) versus 70/100 (high risk). The 1.6 CRDi has 4 documented serious faults, the main one being «MHSG belt tensioner and crankshaft pulley failure (48V mild hybrid)»; the BMW B57 has 3 documented serious faults, the main one being «EGR cooler leaks on the B57 (limited action on the 540d xDrive)».

Risk index

1.6 CRDi

70

High risk · 4 serious faults

Risk index

BMW B57

22

Low risk · 3 serious faults

Lower risk

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

15 sourcesHow we work

Is the 1.6 CRDi reliable?

The U2 D4FB (2009-2018) is a generally robust diesel if well maintained, with known turbo failures in the early units and timing chain problems from 120,000-150,000 km. Its successor, the Smartstream (U3 D4FE, from 2018), has a good reputation, except in the 48V mild hybrid version, which has a belt tensioner and crankshaft pulley fault that can destroy the engine.[1][2][3]

See the 6 of the 1.6 CRDi faults

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.[4][5]

See the 4 of the BMW B57 faults

Side-by-side comparison

Comparison of 1.6 CRDi and BMW B57
1.6 CRDiBMW B57
Technical data
TypeEngineEngine
FuelDieselDiesel
Displacement1,582 cm³2,993 cm³
TimingChainChain
Power90–136 hp265–400 hp
Productionsince 2009[1][6][7][8]since 2015[9][10]
Reliability
Risk index (what is it?)70High risk22Low risk
Documented faults64
Of high or critical severity43
Worst severityCritical severityHigh severity
Main faults
  1. Critical severity: MHSG belt tensioner and crankshaft pulley failure (48V mild hybrid)
  2. Critical severity: Timing chain stretch
  3. High severity: Premature variable-geometry turbo (VGT) failure
  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
Most expensive documented repairup to €1,800Particulate filter (DPF) blocked in urban usePublished figure[11]No reliable data
Which versions to buy
BuyRecommended versions
  • Smartstream 1.6 CRDi U3 (D4FE, 115-136 hp, without mild hybrid, from 2018)[2][12]
  • B57D30 265 hp, single turbo (B57D30O0, 2015-2020)[4]
  • B57D30 286-340 hp, twin turbo with 48 V (B57D30O2/T2, 2020 onwards)[4]
With cautionVersions to be cautious about
  • 1.6 CRDi U2 (D4FB, 90-136 hp, sold in Spain from 2010 to ~2018)[1][13][14]
  • Smartstream 1.6 CRDi 48V mild hybrid (D4FE MHEV, 136 hp, from ~2019)[3][15]
  • B57D30 320 hp, twin turbo (B57D30T0, 2015-2020)[4]
  • B57D30 400 hp, four turbos (B57D30S0, 2016-2020)[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

1.6 CRDi

See the 16 models with the 1.6 CRDi

BMW B57

See the 8 models with the BMW B57

Other comparisons

With the 1.6 CRDi

With the BMW B57

Compare other engines

That is the comparison you are viewing: change one of the two engines.

Sources

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

  1. Motor Kia y Hyundai 1.6 CRDI (D4FB): ficha tecnica, problemas y tuningMotordinámico · Technical documentation · consulted 26 September 2026 · in Spanish
  2. Kia Ceed III: Bekannte Probleme & RückrufeGebrauchtwagenberater · Other source · consulted 26 September 2026 · in German
  3. Kia / Hyundai 1.6 CRDi MHEV Engine FailuresDOHC (especialista en reconstrucción de motores) · Technical documentation · consulted 26 September 2026
  4. Motor BMW B57: fiabilidad y averíasDasercars · Motoring press · consulted 4 October 2026 · in Spanish
  5. Motor BMW N57: diferencias con el B57Dasercars · Motoring press · consulted 4 October 2026 · in Spanish
  6. Hyundai U engineWikipedia · Other source · consulted 26 September 2026
  7. Hyundai Smartstream engineWikipedia · Other source · consulted 26 September 2026
  8. Hyundai i30 Kombi 1.6 CRDi 48V-Mildhybrid Trend (10/20-01/22): Technische Daten, Bilder, PreiseADAC · Technical documentation · consulted 26 September 2026 · in German
  9. BMW B57 (Wikipedia en)Wikipedia · Other source · consulted 4 October 2026
  10. BMW B57 (Wikipedia de)Wikipedia · Other source · consulted 4 October 2026 · in German
  11. Kia Ceed 1.6 Crdi Problemas | Fallos y averías más frecuentesTotalRenting · Other source · consulted 26 September 2026 · in Spanish
  12. Kia Ceed im TÜV-Check 2026: Schwachstellen, Mängel und ProblemeAUTO BILD · Motoring press · published 2026 · consulted 26 September 2026 · in German
  13. Kia and Hyundai 1.6 CRDI (D4FB) engineEngineDNA · Other source · consulted 26 September 2026
  14. Best Hyundai Kia 1.6 CRDI Mods & Upgrades Guide to D4FB TuningTorqueCars · Other source · consulted 26 September 2026
  15. KIA SPORTAGE 2023 - vehicle recallsGOV.UK (Driver and Vehicle Standards Agency) · Official body · consulted 26 September 2026