I just flushed/changed the coolant on my '97 Ford Expedition. Not long after, I took a trip to the dump (~20 miles). When I got there, coolant was leaking out of the rear, in front of the bumper, up above the left frame rail somewhere. Also, there was coolant in the rear sill of the rear hatch. I dumped my garbage, drove home and all leaking had stopped. I'm still within the proper levels of coolant in the tank, so I've only lost a quart @ most, probobly only a pint. I have since taken the vehicle on one or two other trips w/ no leaking noted, this appears to be a one time thing so far. The vehicle does have rear HVAC. Could this be as simple as overfilling my coolant recovery tank, or an ominous sign that ther rear hoses &/or heater core's about to go...?