Hi,i have had this noise, not unlike a hammer hitting a anvil and a was told to run the engine above 3000 rpm for maybe ten minutes or so to get rid of any air that might be trapped in one of the tappets. so off i went up the bypass in ist gear for 5 miles, ok it sounds daft but it worked. i was just about to go on my hols as well, so stripping it down was not an option. t bag