Hi, all,

My truck overheats unless I let it warm up first to operating temperature. I changed the t-stat already (that's about the limit of what I can personally do, mechanically). If I let it warm up, it goes with no overheating problem. If I don't let it warm up, it overheats a few miles into the trip. If I let it cool down and drive it again, it will overheat again. BUT if I do this a couple of times, it will stop overheating.

I've replaced the t-stat and flushed it thoroughly. There is no oil in the coolant and compression tests shows nothing abnormal. The clutch fan turns (infinite number of times) with some resitance if it is cool.

I'm getting a different diagnosis with everyone I talk to. I'm thinking at this point just go ahead and replace the fan, but I don't want to/can't make a bunch of repairs. Any ideas? Edit: after letting it warm up, I turn it off and move the fan. I can turn it by hand -- there is resistance -- several times. Edit 2: the fan also turns by hand with resistance if driven a distance. Any ideas? Anyone?