I have a 97 F150,4.2 V6,auto,77,000 miles..I bought it used with 67,000 miles in Feb.2002..I flushed the radiator in June and since have noticed the antifreeze in the holding tank has dropped about 1/4".Ive looked for leaks under the truck,the motor,inside the truck and have found nothing.Is this just a normal evaporation of the antifreeze?Oh,and the oil is not milky,so i know its not going in the block.Any info. on this is greatly appreciated.

 

You may have leaks that you cannot find, but the amount of coolant you are describing is totally within tolerable limits. I have to add coolant to the overflow on my car about once a month. There is a leak where the heater hose tubes are pressed into the intake manifold, and I cannot make it stop. The coolant, I think, drips down onto the bell housing, and the top of the tranny. It gets hot enough that the coolant is evaporated almost totally before I can find the source of the leak. I have tightened the hose clamps over and over, but still have a leak, and consider it to be 'just one of those things you live with' as the alternative is to replace the manifold. (Sable 3.0 vulcan)
I wouldn't worry about it if the pressure holds good and the hoses are in good shape. I have found that the factory hoses last longer than aftermarket. Factory lasted until 2000. Replaced upper and lower, and the lower let go last June! So, I'd check all your hoses and replace any that were questionable.
tom