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B38A12

B38 1.2 (B38A12, MINI One) engine: faults and reliability

BMW B38 (1.5 gasolina) and B37 (1.5 diésel) de tres cilindros version

With caution

We have found no reliability data specific to this variant: we cannot say it is free of defects, only that we have found none documented. Check the maintenance history.[1]

Years
since 2014
Power
75–102 hp
Faults that affect it
2
0 of high or critical severity
Cars that use it
2
in our database

2 sourcesHow we work

What changes in this version

1.2-litre variant of the three-cylinder family, with 55 kW (75 hp) and 75 kW (102 hp) according to German Wikipedia; fitted to the third-generation MINI One.[1][2]

Engine codes of this version: B38A12.

Faults of the B38A12 engine

The documented engine faults that affect this version and its years, from most to least important.

  1. 1Medium severityFrequency: RareCoolingCoolant leaks and water pump or thermostat failure on the B38Two sources point to the cooling circuit (thermostat housing, electric water pump and hoses) as the most cited wear point on the B38, with leaks from around 70,000 km. The data is scarce and of uneven quality, so it is treated as a risk to watch rather than a widespread fault.
  2. 2Low severityFrequency: OccasionalIntakeCarbon build-up on the B38's intake valves and injectorsAs a direct-injection engine, the B38 builds up carbon deposits on the intake valves and injectors, like other direct-injection petrol engines. The German press cites it as the point to watch in an otherwise trouble-free engine, and it is noticed mainly on short journeys.

Cars fitted with the B38A12 engine

Open each car to see all its faults with this engine and what to check before buying it.

MINI

Frequently asked questions

Is the B38A12 engine reliable?

Our verdict is “With caution”. We have found no reliability data specific to this variant: we cannot say it is free of defects, only that we have found none documented. Check the maintenance history.[1]

What faults does the B38A12 engine have?

The documented ones that affect this version, by importance: coolant leaks and water pump or thermostat failure on the B38 (medium severity) and carbon build-up on the B38's intake valves and injectors (low severity).

Which cars use the B38A12 engine?

MINI Cooper F56 (2014–2024) and MINI Cooper F55 (2014–2024).[2]

Are you buying a car with the B38A12 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. BMW B38 (Wikipedia, alemán)Wikipedia · Other source · consulted 4 October 2026 · in German
  2. Mini Hatch (Wikipedia)Wikipedia · Other source · consulted 4 October 2026