So my zj runs normal temperature typically all the time. It can be 105 outside and I'm doing my normal commute and it doesn't go over 205. Yesterday I was on the trail and it was 90 degrees outside and the jeep was pushing 250. Any ideas?

 

Fan clutch.

 

It's less than a year old and the heavy duty one.

 

New puppies die too. Check and make sure the condenser and radiator fins are not full of bugs and crap.

 

How can I verify the clutch fan is good or bad?

 

I can hear mine cycling when I'm a driving. But you can start the engine and let it worm up, the fan should start moving a lot of air after a while. Once you feel the air is flowing good and is warm, shut the engine down and watch the fan. It should stop pretty quickly. Don't go sticking your hand in the fan with the engine running.

 

I replaced the fan clutch once again and it still wants to run hot in high temperatures at low speeds.

 

Check the electric fan. Without it my XJ will shoot up above 210 in a hurry. Let it get warm, it should kick on when the temps get up above normal operating range

 

It doesn't have an electric fan, only clutch fan.

 

You may have a radiator problem.

 

Brand new radiator and is flowing.

 

Have you confirmed the temperature with a infrared temp gun?

 

Just because it's new, doesn't mean it's any bloody good. Ever hear of a "box failure?" I've run across a few over the years (which is why, if it's something I can test easily, I'll test it before I pay for it...)

 

Even new puppies die.

 

I have confirmed the temperature.