We had a Mini Countryman 1.6 (BMW X1 underneath) in recently which was running very badly. The customer wanted a Carbon clean and all the running issues resolved. This car uses the Peugeot / Citroen 1.6 THP engine.
In 1.4 litre form EP3/EP3C it is found in all these cars Peugeot 307,207 Mini One, Peugeot 308, Citroen C3, and Peugeot 208. In 1.6 Litre EP6/EP6C form it is found in Peugeot 207 Sport, Mini Cooper, 208, 308, 508, Citroen C3, C4, DS3, DS4.
This engine is a joint venture between PSA Peugeot Citroën and BMW. It is a compact engine family of 1.4–1.6 L in displacement and includes most modern features including gasoline direct injection, turbocharging, BMW VANOS variable valve timing.
It’s a good design and works well but like most modern engines, has some weaknesses in the design. The high pressure fuel system – particularly the pump can be an issue. Carbon build up from oil mist is a problem as well as possible major failures due to lack of servicing. Ignore manufacturer service internvals – at least halve them – they don’t want your engine to last and only the most expensive Supercars have anything approaching sensible in regard to oil change intervals.
Compared to the Audi V8’s we see often, these ports were not as bad, but they still had enough carbon on the valves to seriously reduce performance and economy.