03 discovery 104kmiles. Parked it in restaurant parking lot. Got out and had some steam coming out of hood. Took family in restaurant, came back out , steam had stopped and some green antifreeze/water mixture was dripping under the driver's side. Popped hood and looked but could not see anything leaking. Started engine and looked again but still did not see anything. Cut engine off, let it sit a while and checked coolant level and it was fine. Drove the 15 miles home, temp gage never went above normal. Pulled in driveway, checked under hood no leaks. Engine off, no leaks. Completely confused and need some help.