Stopped in to get the oil changed on the truck yesterday and of course they check the radiator fluid. Now keep i mind I've had the truck for close to a year and it has 286K on it. When they drew the fluid out to check it was "MUD"
This truck has never overheated, heater always ran good. Well what would normally take about 15 minutes to flush and fill took about an hour. On the way home the heater ran quite a bit cooler than it used too--reminded me of my full size Bronco I had (I kept cardboard on the front of the radiator in the winter) On the way to work this morning about the time I got to work I was behind a slow poke so I punched to get around them--well that knocked a plug out of the system and the heater started warming up as normal. Although the 5.4L isn't my favorite engine it sure can take a beating and keep on going. I'm sure the radiator fluid has never been changed and has probably been mudded up for long before I bought it.
I am totally shocked the water pump, heater core, and radiator hadn't failed long ago.