B48A20B48B20
B48 2.0 178-197 hp (120i, 220i, 320i, 520i, X1/X2/X3 20i, MINI Cooper S) engine: faults and reliability
BMW B48 (B48A20 / B48B20) / B38 (B38A15 / B38B15) version
Buy
It is the most widely fitted B48 version and has no serious, widespread fault on record; it is worth checking the cooling circuit and any oil leaks next to the turbo and the VANOS.[1]
What changes in this version
The middle power step of the B48 and the most widespread: it powers the 120i, 220i, 320i (in its entry-level version), 520i, the sDrive20i/xDrive20i variants of the X1, X2 and X3, and the MINI Cooper S, with published factory outputs of between 178 and 197 hp (131-145 kW) depending on the model and year.[2][3]
Engine codes of this version: B48A20, B48B20.
Faults of the B48A20 engine
The documented engine faults that affect this version and its years, from most to least important.
- 1Medium severityFrequency: OccasionalCoolingDeterioration of hoses and seals in the cooling circuit, with coolant lossYes: over the years and many heat cycles, the hoses, the expansion tank and some of the plastic seals in the B48/B38 cooling circuit can deteriorate and lose coolant, sometimes without any visible puddle under the car.
- 2Medium severityFrequency: OccasionalLubricationOil leaks or seepage from seals and covers, near the turbo and the VANOSYes: over time, oil seepage or leaks can appear at seals, covers and crankcase ventilation connections, in an area of the engine close to the turbo and the VANOS system.
- 3High severityFrequency: RareTimingTiming chain on the early units (2014-2018), redesigned in the B48TUWe have found no documented cases of timing chain breakage on the B48. The one concrete fact that does exist is that BMW redesigned the chain as a single piece in the 2018 B48TU update, which points to an area for improvement in engines built before that date.
- 4Low severityFrequency: CommonIntakeCarbon build-up on the intake valves (direct injection)Yes, as on most direct-injection engines: because they are not washed by fuel, the intake valves on the B48/B38 build up carbon over the years, especially in urban use, with a loss of smoothness and a less stable idle.
Cars fitted with the B48A20 engine
Open each car to see all its faults with this engine and what to check before buying it.
BMW
- BMW Serie 1 F20118i · 120i · 125i2015–2019[2][4][5]
- BMW Serie 1 F40118i · 120isince 2019[2][4]
- BMW Serie 2 F22220i2015–2021[2]
- BMW Serie 2 Active Tourer F45220i2015–2021[2]
- BMW Serie 3 F30320i · 330i2015–2019[2][6]
- BMW Serie 3 G20320i · 330isince 2019[2][6]
- BMW Serie 5 F10520i · 530i2016–2017[2]
- BMW Serie 5 G30520i · 530i2017–2023[2]
- BMW X1 F48sDrive20i · xDrive20i · xDrive25i2015–2022[2][7]
- BMW X2 F39sDrive20i · xDrive20i2018–2023[2]
- BMW X3 F25xDrive20i2014–2017[2]
- BMW X3 G01xDrive20i · xDrive30i2017–2024[2][6]
- BMW Serie 2 Active Tourer U06223isince 2022[9]
- BMW X1 U11xDrive23i · M35isince 2022[10]
- BMW X3 G45X3 20 xDrive (208 CV, microhíbrido 48 V) · X3 30 xDrive (254 CV, microhíbrido 48 V)since 2024[11][12]
MINI
- MINI Cooper F56Cooper · Cooper S · John Cooper Works2014–2024[3][4][8]
- MINI Countryman F60Cooper · Cooper S · John Cooper Works2017–2023[4][8]
- MINI Cooper F55Cooper · Cooper S2014–2024[3]
- MINI Cooper J01Cooper C (1.5, 156 CV) · Cooper S (2.0, 204 CV)since 2024[13]
- MINI Countryman U25Cooper C (1.5, 170 CV, microhíbrido 48 V) · Cooper S (2.0, 218 CV) · John Cooper Works (2.0, 300 CV)since 2024[14]
Frequently asked questions
Is the B48A20 engine reliable?
Our verdict is “Buy”. It is the most widely fitted B48 version and has no serious, widespread fault on record; it is worth checking the cooling circuit and any oil leaks next to the turbo and the VANOS.[1]
What faults does the B48A20 engine have?
The documented ones that affect this version, by importance: 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 (medium severity), timing chain on the early units (2014-2018), redesigned in the B48TU (high severity) and carbon build-up on the intake valves (direct injection) (low severity).
Which cars use the B48A20 engine?
BMW Serie 1 F20 (2015–2019), BMW Serie 1 F40 (since 2019), BMW Serie 2 F22 (2015–2021), BMW Serie 2 Active Tourer F45 (2015–2021), BMW Serie 3 F30 (2015–2019), BMW Serie 3 G20 (since 2019), BMW Serie 5 F10 (2016–2017), BMW Serie 5 G30 (2017–2023), BMW X1 F48 (2015–2022) and BMW X2 F39 (2018–2023), among 10 others.[2][4][5][6][7]
Are you buying a car with the B48A20 engine?
We will put you in touch with a partner only if you authorise it in the form.
Do you have a car with this engine? Tell us which faults you have had and at how many kilometres. Report your fault.
Sources
Every fact on this page links to its source. If you find an error, let us know.
- Motor BMW B48: defectos, mantenimiento y guía de compraRecambios y Accesorios BMW (blog) · Technical documentation · consulted 27 September 2026 · in Spanish
- BMW B48Wikipedia (inglés) · Other source · consulted 27 September 2026
- Mini HatchWikipedia (inglés) · Other source · consulted 27 September 2026
- BMW B38Wikipedia (inglés) · Other source · consulted 27 September 2026
- BMW 1 Series (F20)Wikipedia · Other source · consulted 29 October 2026
- 5 BMWs That Prove the B48 Four-Cylinder Engine Is Better Than You ThinkBMWBLOG · Other source · published April 2026 · consulted 27 September 2026
- BMW X1 (F48)Wikipedia · Other source · consulted 29 October 2026
- MINI (BMW)Wikipedia (español) · Other source · consulted 27 September 2026 · in Spanish
- BMW 2 Series Active Tourer (U06)Wikipedia · Other source · consulted 29 October 2026
- BMW X1 (U11)Wikipedia · Other source · consulted 29 October 2026
- BMW X3 (G45)Wikipedia (inglés) · Other source · consulted 31 October 2026
- BMW X3 G45: enginesCars-data.com · Technical documentation · consulted 31 October 2026
- Mini Cooper (J01)Wikipedia (inglés) · Other source · consulted 31 October 2026
- Mini Countryman (U25)Wikipedia (inglés) · Other source · consulted 31 October 2026