A QuickFlush Valve, available in four different versions is a simple, inexpensive device, which allows for a thorough, regular, cost-effective, and convenient flushing or winterizing of cooling systems of inboard marine engines, power generators, and A/C units. At the same time after it is easily installed on boats—either by a boat manufactures or by an owner—it offers years of unmatched reliability, safety and convenience of use for the necessary flushing and wintering thus contributing to extended life expectancy and more efficient operation of inboard marine engines, power generators, and A/C units.