Is your coolant topped off? Are you loosing coolant?

Also, when you add coolant, are you adding a 50/50 mixture? Pure water or pure coolant doesn't cool as well as a 50/50 mixture.

96 Contour SE Duratec V6 24-valve 2.5L ATX 108,000 mi. Replaced: crankshaft w/ DMD, EGR valve (clogged), EVR, DPFE, PCV valve, evap emissions hose & tube (cracked), window regulator (broken), LH & RH PCV tubes, UIM gasket (leak), ignition coil