Benzmac is right on the coin. There is no really effective way to "flush" the oil system. Change the oil frequently, maybe every 2,000 miles for about 10,000 miles and thereafter every 3,000, do the filter every other oil change. This should take care of any "flushing" that needs to be done. By adding those aftermarket engine "flushes", all you do is dump a can of solvent into your engine!! This is a real quick way to shorten the useful life of bearings, etc. Frequent oil changes (cheap insurance)..