I have a 06 kx250f and it keeps mixing oil and antifreeze and I am sure of this because I can see a milky substance through the sight glass and my radiators lose fluid I have got a water pump rebuild kit and installed it and also replaced head and base gasket. It does not mix until it runs then after you shut it off it pours out of the "over flow" hose I am out of ideas and open to susgestions