Is this terminal? Update

[rory_perrett]

Thanks to all those who have responded so far. I’ve found a Citroen independent garage about 5 miles form work with all the diagnostic do-dars. Seems a busy place, couldn’t book me in until next weeks so I’m taking that as a good sign. Also liked the fact that the chaps was prepared to talk to me about the problem even before I’d committed to booking the car in for a diagnosis session.

His thinking, without seeing the car, is that it is more likely to be mechanical, suggested changing the oil and filter anyway which I did last night. No sign of water in oil or vice versa so still paying the cylinder head gasket is still OK.

Going to show my ignorance here, I’m assuming the 12 valve engine is 2 inlet, 1 exhaust. Would a failed hydraulic tappet give the symptoms? How do / can hydraulic tappets fail. If one valve was not opening properly (or at all) presumable this would mean less air in the cylinder but the injector would supply the same amount of fuel effectively leading to over fueling and giving the black smoke and reduced power. It could possibly explain the increase in mechanical noise.

Anyone any experience of this? Might it be worth whipping off the cam cover and having a look or (as a desparate man looking for an easy fix) I'm I way off?