My garage advises that they have to change the balance shafts on my Land Rover Discovery Sport (less than one year old with 9300 miles). They will not advise why, only that the engine is making an unusual noise. If it has to do with lubrication, I have asked them to replace the engine, as there may be other long term problems. I have checked the internet and there are other instances of the same problem. In most cases the engines have been changed, but my garage insists that is not necessary.