Advice vs pros and cons of engine flush
Don't know of the wisdom but an old
Engine cleaning truck is to put a quart of diesel in place of a quart of oil and drive it that way for a short length of time.
I had a 460 Ford that lost the dist drive shaft.
I pulled a valve cover off and it was caked in wax like goo.
I drained the oil and filled the crank case with diesel and spun the oil pump with a drill and the occasional rotation of the crank
After some time the waxy goo desolved into the diesel and things were as clean as a baby's butt.
Drained it all filled with oil, new filter,
And drove it that way for years.