Originally Posted by Mxfrank

Actually, he didn't, because both ends of that hose are on the high side of the pump. If the hose flowed even a little, it would either be moving the very hottest coolant to the rear port, or it would be moving cool coolant away from the rear and into the radiator. The one thing it absolutely wouldn't accomplish is to add cool fluid to the rear. I'm guessing that only a small amount of coolant actually flows through that hose, and only when the thermostat is closed.