wallyranger

I have a 2002 4.0L 4x4 XLT Ranger with about 170,000 miles. Two weeks ago, with temperatures in the mid 90's, I had to drive about 60 miles at highway speeds. About 20 miles into the trip, I noticed the temperature guage was above the mid-point. My recollection is that the guage had always been at mid-point or below so I started watching it. It slowly rose to just shy of the red line when I made my destination. It never overflowed. After it cooled, I checked the coolant level which was full. On the way home that evening, following the same route but with temeratures 15-20 degreees cooler, it stayed at mid-point. Took it to the mechanic. He replaced the coolant and the put in a 195 degree thermostat. Took it out on the highway where the guage stayed pretty much at mid-point but after about 40 miles, I got off the highway and drove stop and go for about 5 miles and the guage rose to near the top but not in the red. They put the meter on and the temp was 250+.. I mentioned that he replaced the fan clutch a few months ago. He said if felt like the fan wasn't drawing air like it should so he replaced the fan clutch again. I drove about 520 miles yesterday. As long as I stayed at highway speeds, the guage stuck to the middle. When I got into stop and go traffic, it went above the mid-point but now it only went about a quarter of the way up between mid-point and the top.

Is this normal?

Thanks for your comments and suggestions.
WALLY