I personally think it is a bunch of [censored]. There are so many detergents in oil nowadays that you should never have to flush your engine as long as you are taking care of your vehicle and are doing oil changes on time. I have been told by many automotive technicians that it can actually do more harm than good and even looking at most manufacture service intervals and recommendations not one of them have ever advised doing an engine flush. I would love to hear what others opinions are and their experiences with HIGH detergent oil cleaning products.