I looked through the threads about over heating problems, but never really found an answer to my problem so I figured I would just make my own. Almost every one said check e-fan or the clutch on the other fan. Try this and that, but I do not want to just start throwing parts at it hoping to fix or hide it. With that said...

About 3 months ago I picked up my 96 xj 5spd 4x4. The only thing I noticed wrong was the D.W. at 45mph, well once the weather started getting warmer, I noticed after taking the jeep off road it was a little over 210. I was on my way home and it went back down and I thought hmm, I need to keep an eye on it. Well the next time I drove the jeep it wanted to over heat, so I figured I had mud in the fins, so I washed everything off/out, still overheated. I then flushed the system and installed a new t-stat, did better, but still wants to overheat. Here is the kicker, it only does it after about 20mins of driving on the highway 60-70mph. I can drive all day under 45mph, sit all day, off road all day and never have a problem, yet get over 45mph and the temp will go up.

I did notice that once the temp went up, the power went down, it felt like I was pulling a trailer in a matter of minutes. Once I would get off the highway and cruise at 45mph, or stop at a traffic light, the temp. would start to drop. Turning the heat on also would help the temp go down. Also, please keep in mind this whole time I have had the AC blowing and it blows very cold. Temp seems to stay closer to normal with the AC off, like the motor doesn't have to work so hard.

Any ideas?

What do you mean "It wants to over heat"???
Is it over heating? How High is the temp getting?
Normal operating temp for the 4.0 is 210deg.

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Check the tension on the serpentine belt. It might be loose causing it to slip at higher rpms making your water pump work slower.

sounds like a water pump to me

I read somewhere that the lower hose should have a spring to keep it from getting pulled closed while higher rpms, wiuld i be able to feel the spring?

I would only have a spring in it if you put a hose with the spring. Not all of them have it.

Well, a small update, this morning I drove the jeep to work. Its about a 40min drive going about 65mph and it stayed at 210 with the ac off and the windows down.

Gonna have to throw some parts at it sooner or later.......it's called preventative maintenance. How old is the radiator, fan clutch, hoses, rad cap and water pump? Usually, when all cooling system components are replaced at once, there's no guessing game 'cause there's no overheating. Money spent on cooling system maintenance is never wasted.

I read over your problem. Did you have the AC on the other times where its been getting hot? Sounds similar as to what I had. It only happened to me on the high way. My AC compressor the clutch had seized up and the belt was forcing it to turn and just grinding that bearing to hell. It would heat me up, never to over heating though. Take a wrench to the clutch and see how much force its giving you back. Maybe that's what's eating you. Worth a shot.

Everything looks factory/original, the PO has a little book with all his work, I will look at it and see what all HE replaced, I don't believe he was the original owner. The jeep just turned over 203k, and now that I think about it, I see where your coming from.

Yes, anytime it would overheat would be able the AC was on, it might be like you stated, but I know sitting there the compressor/fan will kick on and off.

Not trying to hijack but what if his belt was over tightened?

It might squeek or ruin the bearing on the pump and the belt would wear out faster.

Just looked through the book and only thing coolant system related was a t-stat replaced at 200,000, so it looks like I get to start replacing old parts.

Time for a Hesco water pump and a aluminum Champion 3 row radiator???