I use a flush each time I change the oil. I figure it helps clean some of the crud out of the engine and that is the purpose of an oil change. You put detergent in your wash machine don't you?

If you pour the flush on a dirty grease spot, you can see how it disperses the dirt in the spot which just pouring oil on the spot wouldn't do. This proves to me that the flush helps clean the internal parts of the engine.

I realize that this is an individual preference so some do and some don't. Everybody has their own procedures.

P E H