BMW B38 / B37 vs BMW B48 / B38: which engine is more reliable?

According to our risk index, the BMW B38 / B37 carries less risk than the BMW B48 / B38: 20/100 versus 24/100 (both low 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 B48 / B38 has 1 documented serious fault, the main one being «Timing chain on the early units (2014-2018), redesigned in the B48TU».

Risk index

BMW B38 / B37

Low risk · 1 serious fault

Lower risk

Risk index

BMW B48 / B38

Low risk · 1 serious fault

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

Reviewed on 30 October 202614 sources How 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 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).^[4][5][6]

See the 4 of the BMW B48 / B38 faults

Side-by-side comparison

Comparison of BMW B38 / B37 and BMW B48 / B38
Item	BMW B38 / B37	BMW B48 / B38
Technical data
Type	Engine	Engine
Fuel	Petrol	Petrol
Displacement	1,499 cm³	1,998 cm³
Timing	Chain	Chain
Power	75–231 hp	136–312 hp
Production	since 2014^[7][8][9]	since 2014^[4][7][10]
Reliability
Risk index (what is it?)	20Low risk	24Low risk
Documented faults	3	4
Of high or critical severity	1	1
Worst severity	Critical severity	High severity
Main faults	Critical severity: B38 crankshaft thrust bearing failure (units before April 2015) Medium severity: Coolant leaks and water pump or thermostat failure on the B38 Low severity: Carbon build-up on the B38's intake valves and injectors	Medium severity: Deterioration of hoses and seals in the cooling circuit, with coolant loss Medium severity: Oil leaks or seepage from seals and covers, near the turbo and the VANOS High severity: Timing chain on the early units (2014-2018), redesigned in the B48TU
Most expensive documented repair	No reliable data	No 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^[11] B37TÜ1 1.5 diesel 95-116 hp (from late 2017)^[12]	B38 1.5 136 hp (MINI Cooper, 118i)^[5] B48 2.0 178-197 hp (120i, 220i, 320i, 520i, X1/X2/X3 20i, MINI Cooper S)^[5] B48 2.0 252-258 hp (330i, 530i, X3/X4 xDrive30i)^[5][13] B48 2.0 up to 302-312 hp, high performance (MINI John Cooper Works, BMW X1 M35i)^[5]
With cautionVersions to be cautious about	B38 1.2 (B38A12, MINI One)^[8] B38 1.5 136 hp up to April 2015 (B38A15)^[1] B38K15T0 231 hp (BMW i8)^[14]	None
AvoidVersions to avoid	None	None

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 B48 / B38

See the 20 models with the BMW B48 / B38

Other comparisons

With the BMW B38 / B37

With the BMW B48 / B38

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Sources

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

BMW Dreizylinder: Dauertest-Probleme des B38 behoben?BimmerToday · Motoring press · published 5 October 2017 · consulted 4 October 2026 · in German
2024: BMW recall due to EGR coolers extended againcar-recalls.eu · Motoring press · published 28 March 2024 · consulted 4 October 2026
BMW diésel Europa: llamada a revisión por el EGR y riesgo de incendioDiariomotor · Motoring press · consulted 4 October 2026 · in Spanish
BMW B48Wikipedia (inglés) · Other source · consulted 27 September 2026
Motor BMW B48: defectos, mantenimiento y guía de compraRecambios y Accesorios BMW (blog) · Technical documentation · consulted 27 September 2026 · in Spanish
BMW Reliability Has Changed, But the Internet Hasn't Caught UpBMWBLOG · Other source · published January 2026 · consulted 27 September 2026
BMW B38 (Wikipedia)Wikipedia · Other source · consulted 4 October 2026
BMW B38 (Wikipedia, alemán)Wikipedia · Other source · consulted 4 October 2026 · in German
BMW B37 (Wikipedia)Wikipedia · Other source · consulted 4 October 2026
BMW B48Wikipedia (alemán) · Other source · consulted 27 September 2026 · in German
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
BMW Baukasten-Diesel: Mehr Infos zur TÜ1 für B47 und B37BimmerToday · Motoring press · published 20 November 2017 · consulted 4 October 2026 · in German
5 BMWs That Prove the B48 Four-Cylinder Engine Is Better Than You ThinkBMWBLOG · Other source · published April 2026 · consulted 27 September 2026
BMW i8 (Wikipedia)Wikipedia · Other source · consulted 4 October 2026