Hello, the problem of 3,0dci is injection pump (not sure with the correct translation).
You shall buy something like this:
it is a cleaner for diesel engine, i dont have a link fo UK pages. you shall put the this into a PET bottle, put the intput from pump inside, output too and start the engine only for this liqui moly – the problem is that on this pump are two "valves" which are used to die because of dirts inside of the diesel. When you will be finished, it is recomended to change the diesel filtre. The engine shall work much better (starts, not smoke, sound, etc.)
the engine can work for 45mins cca for two bottles of liqui molly