Why does our Honda CR-V emit black smoke when we accelerate?

I have a 2009 Honda CR-V CDT-i with 60,000 miles on the clock. Under heavy acceleration there is black smoke out the exhaust - a fair amount. We have done 5000 miles in the five months since buying it and used one litre of oil. The Honda dealer says that they cannot find a problem. Once there has been some embarrassing black smoke, it seems fine and will not do it again. Under normal driving conditions it is fine. We live in Cornwall and spend a lot of time on country lanes, we only use the dual carriageways every few days. Should we be worried and asking for a proper diagnosis from the dealer? If so, I would think it was covered as it was reported to them within the three month warranty.
I'd suspect the turbo bearing oil seal. Could also be the valve stem oil seals, but the turbo bearing oil seal is the most likely and if that's the case the best solution is a replacement turbo together with new turbo bearing oil feed and oil return pipes.
Answered by Honest John on

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