Just so your clear, you shouldn't use Kroil mixed with your oil.
Why not? I've been using Kroil for over 30 years, and a few ounces mixed in with the motor oil does an excellent job of cleaning up sticky check valves in hydraulic lifters, etc. It will clean out carbon deposits under piston rings, and maybe cause an old, worn out engine to start using oil if the only thing holding the rings against the cylinder walls is the carbon buildup under them. In a reasonably healthy engine, Kroil won't hurt a thing, and usually cleans up the insides quite nicely. 1/2 pint added to the crankcase about 500 miles before an oil change works very well for me, just don't run it as an all-the-time additive.
Jerry
