it's running too hot if in fact it's that hot .... start at finding out what your temp guage means when it sez 250, compare with a good thermometer in the rad, or preferably onea the laser thermometers so you don't have to open the rad, check at both sides of the thermostat housing and top/bottom of the rad, see if you have flow and are getting cooling, the gauges on these ol trucks don't always tell the tale

Bill


Moved over to the Passing Lane

"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir
"When we tug a single thing on an old truck, we find it falls off" ~ me
Some TF series details & TF heater pics