Rapid loss of coolant only when engines running , why? on 2003 Ford Explorer Sport Trac

Yesterday while driving, within about 10 miles the temp gauge when from fine to HOT , the "check" gauge light alarm sounded...I pulled over and the coolant pored out onto the ground from right side (while facing the vehicle) this is a 2004 Sport Trac. With 70,000 miles. A few days ago, the gauge slowly went from normal to HOT but the loss of coolant seemed to be slower as well. I added the proper ford coolant and distilled water combo and let the truck cool down for 2 days...NO leakage under the vehicle at all in either case while truck was parked. What could be the problem? I appreciate your response...

by in New Richmond, WI on August 04, 2013
1 answer
ANSWER by on August 05, 2013
check where upper radiator hose connects to engine. that will be the thermostat housing. made of plastic. usually cracks. replace a lot of them.