I noticed a slight tapping noise in the engine which gradually went, however a week later after using it most days has now left it tapping constantly and louder. A mechanic suggested an engine flush since the origin of the tapping was not coming from the expected location. I feel that an engine flush will just incure more cost because i dont think that will solve it. The tapping increases as the revs increase. If anyone could offer advise i would be gratful.