timricard

So I have a 91 Loyale 4wd (actually my girlfriends) I have been getting it ready ot go on a long road trip and recently flushed the radiator. THe car is just flying throught coolant, I cannot find a leak anywhere (I let the car run for 45 minutes and could not find a drop on the ground) THe car is running great and does not overheat but the boil over resivoir is empty after about 50 miles. I would love any suggestions as to what to do thanks..... Tim