XJCrAzY29

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

djb383

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

thakmfb

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.

XJCrAzY29

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

djb383

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

djb383

Big tires, big winch blocking air flow?

XJCrAzY29

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

XJCrAzY29

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

djb383

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

beat up jeeper

csf 3 row is a good one

tjwalker

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.

XJCrAzY29

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

Radi

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)

XJCrAzY29

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

XJCrAzY29

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?