I am coming to my wits end with my xj. I cant seem to keep it cool in this heat. I understand these jeeps run fairly hot anyways but i have to figure this out. It will climb to 220-230 with ac on in 90f weather. I do a lot of hill climbs that puts some stress on the engine. Temps climb up to 220 range with ac off when I go up most hills. the jeep has 90,000 on the engine and about 290,000 on the rest. It does have a 6" lift and 35's also regeared to 4.10's. If the ambient temp stays below 85f i am fine but i live in utah and see higher temps

To start with the parts that have been replaced in the last 10,000 miles

Cylinder head rebuilt and new head gasket
new water pump
oem temp thermostat 195f
2 row radiator
ac condenser
upper radiator hose
lower radiator hose
new radiator cap
trans cooler
spaced the rear of my hood up(i know its not safe but im desperate)
heater control valve.
tried ford taurus fan swap
currently have zj fan clutch
newer xj ac electric fan
aftermarket temp gauge.

trans seems to be getting pretty hot lately but haven't got any real temp readings. I would love to get it to the point where i can tow my fourwheeler but cant do that with it heating up. lol I am beginning to debate an engine swap if i cant figure this out

any help or ideas would be greatly appreciated

 

How do you know if the bottom third of the radiator is not clogged with scale and rust? Just Askin................

 

i guess i dont know. I was just hoping since i replaced that last year it wouldnt be bad already

 

Edit. Missed that you already have a trans cooler.

 

Thoroughly reverse flush radiator and heater core. Observe what comes out.

If it is clear, put it back together with 50/50 coolant. This is the best your Jeep will do. It's not REALLY hot until it hits 240 or so.

If it is rusty, brown, gunky, find out why before proceeding further.

 

He said he already has trans cooler in the last year or so.

 

Ok, hill climbs in 90 plus temps with the AC on. You don't sound unreasonable based on conditions. Consider hood louvers, it won't cool the engine but it will reduce the under hood temps which does help intake air temps.

X2 on the flush advice above.

 

I chased this problem on my 00' XJ FOREVER. Just last month (after an engine rebuild and a brand new radiator) I noticed some air blowing OUT from the radiator. The electric fan was wired to run in reverse FROM THE FACTORY. Sorry for the caps lock..... The green (oh no, it's not a ground, WAS run to ground, but it needed to be fed with 12V. The black is now run to ground. It spins the right direction and makes roughly a 15 degree difference. I wonder how many XJ's are backwards like this....

 

I have similar behavior with my 98 XJ. Never overheated, but doesn't have that margin of safety in extreme conditions. Always been a little nervous about that creep to 220 degrees climbing up a hill at 70 mph on a 90 degree day with the A.C. on. Also worth mentioning is that my upper hose gets rock hard after I shut down the engine. As the engine cools, the pressure goes down. No leaks, no fluid loss. Like Cheddarnut and Firestorm 500 implied, maybe the nature of the beast?

 

maybe i should clarify about my radiator. i bought it froma store on ebay so i dont think its a very reputable company. has anyone had problems with radiators from there

 

If it's not leaking, it's probably OK.

Just because you bought it on eBay doesn't make the company disreputable.

 

My 98 Sport was always running hot also. I put a 3 core aluminum radiator plus new hoses in, Flow Kooler water pump, Trans cooler and K & N filter system along with 180 radiator cap and hood louvers. Runs right at 180 to 190 even during playtime. It just drove me nuts when it went over 200 now it's great.
JPLUG

 

4.0 operating temp is 210

 

Big problem that I see are the 4.10 gears and running 35" tires, this is the correct gear if your running 31" tires. Here is where all the extra strain on the engine is coming from on the hills.


I run 2 sets of tires one a set of 33's the other 35's and a 4.56 gear on the 35's you can tell it need a bit more gear but I didn't want the weak pinion of the 4.88 gears so stayed with the 4.56 setup.


Do a gear change and see if that doesn't cure the problem.

 

Who has $1000+ to regear to see if that fixes a problem ? Not me.