Originally Posted by Wild Thing
its only the N14 cooper s engine that suffers and needs a decoke. Your engine would have been fine, it probably crap coming out of the exhaust system you were amazed at.
the N14 might be the noted mini engine that suffers , but mine had several female owners previously that had only used the car for small trips and therefore the engine had coked up.it has 75000 miles on the clock and had never been decoked before. the amount of black crap that came out was astonishing , the hydrogen clean clears the inlet and outlet manifolds and the exhaust/cats so the buildup could have been at any of these points. the one thing I do know is that the car is not now smoking at standstill or changing gears and the throttle response is much better , so I deem it worthwhile . all cars coke up over time , a lot depends on what fuel / oil you use and how you drive the car.