Need some thoughts on where to look for the problem. I have a 1998 F700 with a 7.0 MFI and the temp gauge is reading on the Normal about at the L. changed the thermostats out, installed new header tank and the pressure cap along with new antifreeze. Will sit and idle and never get past the O but if I drive it around the block it climbs up to the L really fast. Any input on the possiv;le problem> Radiator is clean, fan clutch seems to be working. Appreciate all the help I can get