I really don't understand the reasoning of flushing the old oil during a oil change. If you warm up the engine before draining the old oil, very little old oil is left in the crank case after the draining occurs. This has been the process for a 100 years. Keep in mind, we're not talking a super high priced collectible car here, these are DAILY DRIVERS and will do just fine by simply DRAINING the warm oil!!!