Carbon build-up in the intake MINI: problems by model and engine

Documented faults, from most to least important

Severity × frequency. Below each one, the MINI models it appears in.

- Medium severityFrequency: Common1.6 HDiLeaks at the injector washers and carbon build-up in the cylinder headIt is common for the copper washers of the 1.6 HDi injectors to stop sealing: the engine blows gases, carbon forms around the injector and soot gets into the oil. It is cheap to repair, but if left it contaminates the oil and is one of the causes of turbo failure.Repair (garage): €110–€310
In Cooper R56
- Low severityFrequency: CommonBMW B48 / B38Carbon 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.
In Cooper F56, Cooper F55, Cooper J01, Countryman F60 and Countryman U25
- Low severityFrequency: OccasionalBMW B38 / B37Carbon 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.
In Cooper F56, Cooper F55, Cooper J01, Countryman F60 and Countryman U25

By MINI model

Open yours to see only the faults that affect it, by engine and by year.

Engines and gearboxes involved

Frequently asked questions

What faults with carbon build-up in the intake do MINI cars have?

In 6 models from MINI there are 3 documented faults with carbon build-up in the intake. The most important: leaks at the injector washers and carbon build-up in the cylinder head, carbon build-up on the intake valves (direct injection) and carbon build-up on the B38's intake valves and injectors. Each fault has its own page with the affected years and versions, the symptoms and the repair cost.

Which MINI models have the most problems with carbon build-up in the intake?

MINI Cooper F56 (2 faults), MINI Cooper F55 (2 faults), MINI Countryman F60 (2 faults) and MINI Cooper J01 (2 faults).

Which MINI engines have faults with carbon build-up in the intake?

1.6 HDi (1 fault), BMW B38 / B37 (1 fault) and BMW B48 / B38 (1 fault).