V6, V8?
I was having some issues, ended up bleeding the coolant about 47,591 times to no effect. Put a new water pump on, no change. New fan clutch, fixed it for about 45 minutes. New coolant, no change. New t stat, no change.
Finally did some research, put a CHT sensor in and now it's fine. Fan runs hard if the AC is on and I've been driving it hard or it's really hot like it has been lately here.
The sensor I refer to is under the intake, on the passenger side head. The intake is a bit of a pain in the ass to take off, but the sensor is easy to get out once the intake is lifted up about 6-8 inches.
You might also disconnect your Pos batt cable for a bit afterwards, pump the brake pedal 4-5 times to clear the PCM...(unless this trick doesn't work on 4th gens like it does older ford stuff...?)
