Sorta kinda overheating while moving/closed system

Hey gang-
Last week (while tracking down my AC fix) I replaced the radiator in my 88 xj with an all aluminum one, I've got a Mac's AL bottle, new upper & lower radiator hoses, new overflow 16 PSI cap (though I didn't need one), new 195 degree thermostat, and I've noticed that instead of the gauge tracking smack dead-on the halfway mark and not moving at all like it has for years/decades, it's just a bit over (hotter) now. No big deal, until I noticed that for the 3rd time since the above fixes it's now running hot...like @ the 75% mark (just barely ahead of the red) while moving @ 75mph on the freeway. Today it pegged to WFO, passing and moving right on thru the red zone like it wasn't no big deal, as I pulled in the garage after heading up my canyon. It did not puke coolant at all as it cooled, no gurgling sounds, and the coolant level in the mac's bottle is still good. I've heard of cooling problems while running slow/crawling thru traffic, but @ speed? I was thinking/wondering if I needed a fan clutch, but 2 shops told me mine was A-OK. The fan clutch stops immediately after turning off the key, and the electric fan works and comes on with the AC and automatically.

Any thoughts?

-greg

could be a bad temp sensor.

There are lots of threads with this issue. Seems to be a common problem with a lot of different answers.

Since you changed so much in your system, it may still have air trapped in some of the hoses. Another possibility is that your temp sensor's whacked like justkain says.

A bad fan clutch would typically cause a slow speed/idle overheat since there's little to no air moving through the radiator. This is not a problem at 75 mph unless the radiator is clogged with mud/dirt. Since you just changed it, I'm guess it's not clogged.

Trapped air would reduce the amount of coolant flowing through the system. It's common for closed system XJ's to require "burping" to rid the trapped air. You can search on this to find out more.

Found out it IS a bad temp sensor. Jeep says there's a notional backorder for it. Any of youse guys got one you wanna part with?

Pretty please?