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B48A20B48B20

B48 2.0 252-258 hp (330i, 530i, X3/X4 xDrive30i) engine: faults and reliability

BMW B48 (B48A20 / B48B20) / B38 (B38A15 / B38B15) version

Buy

It shares its block and architecture with the rest of the B48; we have found no serious, widespread fault on record that is specific to this more powerful version.[1][2]

Years
since 2015
Power
252–258 hp
Faults that affect it
4
1 of high or critical severity
Cars that use it
5
in our database

3 sourcesHow we work

What changes in this version

The higher-output step of the standard B48 (short of the John Cooper Works versions), with a higher-flow turbine; it powers the 330i and 530i, with published figures of around 255 hp, and the xDrive30i variant of the X3 and X4.[2]

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.

  1. 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.
  2. 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.
  3. 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.
  4. 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

Frequently asked questions

Is the B48A20 engine reliable?

Our verdict is “Buy”. It shares its block and architecture with the rest of the B48; we have found no serious, widespread fault on record that is specific to this more powerful version.[1][2]

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 3 F30 (2015–2019), BMW Serie 3 G20 (since 2019), BMW Serie 5 F10 (2016–2017), BMW Serie 5 G30 (2017–2023) and BMW X3 G01 (2017–2024).[2][3]

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.

  1. Motor BMW B48: defectos, mantenimiento y guía de compraRecambios y Accesorios BMW (blog) · Technical documentation · consulted 27 September 2026 · in Spanish
  2. 5 BMWs That Prove the B48 Four-Cylinder Engine Is Better Than You ThinkBMWBLOG · Other source · published April 2026 · consulted 27 September 2026
  3. BMW B48Wikipedia (inglés) · Other source · consulted 27 September 2026