Ok i have a 96 xj, new thermostat, new electric fan, new clutch fan, fresh coolant flush. When cruising in town or at idle it doesnt run hot about 210, but as soon as i hit highway 70-75mph or hit the slightest incline it runs up about 240ish-250, im puzzled any help would be appreciated. Thanks

 

U stopped too soon.....new water pump and radiator and most likely the overheat is solved.

 

Water pump? But sounds like a fan clutch issue. Could be at the higher rpms the water pump is failing and you arent getting proper flow. I have come to learn that these cooling systems dont follow traditional rules for diagnosis. Maybe a radiator cap too. Since at higher RPMs there is more flow and maybe more pressure? I dunno really parts are generally cheap, so I would go with the shotgun approach and and throw everything at it.

 

Thats just recent parts within last 3 months, also put a new rad and water pump on about a year ago.

 

At highway speeds, fans/clutches shouldn't be an issue as there should be more than enough airflow.

 

Big tires, big winch blocking air flow?

 

33x10.50's, has a winch now but did the same thing before the winch..

 

Well guess ima replace the rad, any suggestions on a good replacement?

 

What's happened a year old rad? Any warranty left?

 

csf 3 row is a good one

 

I agree with djb here...

Overheating at highway speeds but NOT at idle is usually related to water pump or radiator not being able to keep up.

 

So update, replaced the Rad, water pump, 180 tstat, new hoses, new clutch fan, new elec fan and still having overheating issues, fresh flush and all

 

Just for giggles, check the temperature at your thermostat housing with an IR thermometer.
I wonder if your gauge sender is non-linear at higher temps, causing it to read wrong?

How's the engine running? Sometimes fuel or timing problems can make engines run too hot. Fuel starvation causing a too-lean condition at high RPM isn't unheard of. Taping a fuel pressure gauge up where you can see it while driving sometimes is interesting.
A partially obstructed Cat is another possibility, which the '96 had big problems with. (There is still an active campaign on them)

 

See i was thinking the same thing cause i have seen the gauge at 250ish and it wasnt boiling off any coolant or anything? but still seemed warm when i popped the hood

 

And just a random thought i was having, maybe pulling around those 33's on the stock 3.55's maybe its alot of load on it, but didnt know?