Hey guys .this is my first post ever. I've usually been able to figure out things myself but i'm stuck on this one.

so here it is.

Ever since i got the jeep ive replaced the heater hoses, lower and upper radiator hoses, and converted my stock clutch fan and electric fan to the three row electric fans and work great. On the the streets, heavy traffic or cruising on the freeway my jeep stays well under 210 the whole time but once i start offroading and engaging 4wd is where my temp starts creeping up to 220 240 and its even gone all the way to 260! now since the jeep always stays cool when not offroading i assume all cooling components are working as required? do i need to upgrade my radiator? does the transmission temp have anything to do with this?

i really appreciate your help!!

in my experience, all those 3 row fan kits suck. the factory mechanical fan with a functioning clutch and the stock efan (especially the newer style 10 and 11 blade ones) work great.

If you're gonna redo the fans you should use dual Taurus dohc fans.
What year xj? Open or closed loop cooling?

1991 xj. open cooling system.
i heard good things about those fans but also that it needs a lot of modding to fit them in :/

ohh dont tell me that i worked real hard on putting those on haha but whatever. u think upgrading my radiator to a better one might do a difference?

I'm running a stock clutch fan with a spal electric fan with a CSF rad. No issues in the woods since the work.
You obviously have a problem with air pulling though.

When I did maint. on my cooling system, I flushed the system 3-4 times. I replaced the thermostat and checked the water pump (it was good). I did the ZJ fan clutch upgrade and since I don't use my A/C (didn't work anyway) I removed the A/C condenser between the grill and the radiator. This lets a LOT more air through. You might just check the condenser and make sure that it's not clogged up on the outside with bugs and such. I usually spray a water hose through my radiator once in a while (in warmer months when the bugs are out) and make sure that the fins aren't clogged.

Confirmed the temps with an IR gun? XJ gauges aren't exactly scientifically accurate in the first place, but a malfunctioning one can appear to work but display incorrect temps. You may very well be running cool on road and simply running higher offroad, but not overheating.

no definitely overheating. when i stopped and popped the hood there was antifreeze boiling over the reservoir tank . and yes ill confirm the temps just to make sure.

No hijack intended, I am having this problem as well, but I have never had coolant boil, so I'm thinking it couldjust be my guage

is your fancy new fan system a push or pull system.
you may be pushing when you want them pulling...

also, make sure they have an adequate shroud around each fan tight to the rad.

if your stock rad is junk, then yea. but a 100% functioning 100% stock cooling system works great. mine is 100% stock save for the CSF 3 row rad (which really isnt a huge improvement over a stock 2 rad... but its nice that its all metal) and i run 210-215 at most on the highway, in traffic, on the beach, etc.

Take out your thermostat open the windows and crank the heat. Or take your hood off.and it never hurts to unclog your hoses and flush your coolant. 4.0s are hot little suckers.

Why not fix it?

From what he said there doesn't seem to be anything wrong with it. It stays cool when on road but starts getting hot when he goes offroad, that seems to be the case in 100% of the xjs I've ever been around. And there are small cheap ways to keep it cooler.