'96 2.7L 4x4 overheating issues?

Recently my 96 4x4 2.7L tacoma has been overheating. It has 192,000 miles on the clock on a used engine and 292,000 on the chassis. It will run normally around town for days and then if I hit highway speeds (65-80) it will overheat. If I stop for a few minutes the temp will go back down sometimes for a mile, sometimes for 5 miles before going back up. Turning the heat on doesn't seem to effect the temp and I have had some issues with the heat not working so well in the winter. I may have just answered my own question. Haha. If I let it sit overnight it will run fine for days and the cycle continues. The radiator is 2 years old and I've checked the fan clutch with the rolled up magazine trick and I'm tempted to replace the thermostat but wanted to check here first to see if I'm missing anything. The fluid is fine and I'm not noticing any fluid leak from the hoses or water pump. Thanks for any help!

 

Well you said the rad is only two years old, but I had those exact same symptoms and I replaced everything with no avail, until I swapped radiators and bam that was it. Fan clutch doesn't really kick on fully at highway speeds so I'd doubt that it....

 

If you ever play in mud check to make sure it's not caked in your radiator. Pulled mine completely out and hosed it out. Running 190f since.