the thermostat is new but i can't rule out that it is faulty. when the temp shot up the efan was already on, it comes on at 210 (normal?) only other symptom is the coolant. it was higher in the reservoir than normal. probably would have spewed if i hadn't cooled it down.

 

instantly shot up got me thinking sensor

 

is the temp sensor just for the guage, or does it perform any other tasks?

 

gauge,fan,and sends a signal to the computer

 

so i may have a faulty therm. the temp just spiked to it could be temp sensor. the fluid wants to spew out of the reservoir so could be water pump. sounds like i have a lot of things going on. plus the speakers in the front doors don't work and i think all four of the tires are flat. i might want to check the tail pipe for a bird nest too

 

did this start after the thermostat was replaced????

 

i replaced the therm this past summer along with the radiator.

 

id do a nother thermost and a cap

 

i'll head out now and pick that up and let ya know how it turns out. is the temp sensor the thing threaded into the spot where the therm goes?

 

yes

 

While your out pick up a infrared thermometer, point it at the Tstat housing to verify gauge is correct. I agree new Tstat, rad cap, get the Stant superstat, not the store brand.

 

hi there guys i owed 5 xj's and just got another one and going to start the build ,on all xj i had did all cleaning new water pumps fan clutch and radiators still over heated, so what i do is change to a 91 xj radiator lose the dumb plastic bottle, reroute heater hoses and most important put a switch to the eletric fan on the left side of radiator ,i found that this is the only thing that lowers the temp when i first started on xj's i tried all the aftermarket things high flow tremostats, high flow housing three row radiator high flow water pump did not help! what i think is that mech.fan only cools half the rad. thats my believe and i will stick to it on the new build . i am new to forum hope this helps all xj;ers

 

Standard cooling only has one fan (belt driven) and my guess is when the vehicle was new, or only a few years old, overheating, in most circumstances, was a non-issue, even with only 1 fan. I think the dinky radiator (small sq. in. front surface area) is the weak link in the XJ cooling system when operating in high ambient temp, a/c use and slow vehicle speed scenarios. Usually, whatever band-aid is not needed in most driving conditions, especially this time of year, when the XJ has a proper tune, maintenance has been performed and all cooling system components are in good condition/performing as designed.

 

I've had myriad cooling problems (or, rather, not-cooling problems) with my '95 XJ. I've been through three JY engines. Two of them apparently had water jacket problems--cracks or something. It was easier to just get another one than try to track down whatever the problems were. They both overheated badly.

The engine I'm running now is an "out of a 2003" 4.0L, but I don't know what model Jeep. In trying to solve the overheating problems in the other two engines, I replaced radiator, water pump (it leaked out the bottom), and tried several T-stats. The new water pump was installed on the third engine, as the water pump that was on it was seven years old.

This engine has been in my XJ and running good for a year, but I live in Houston and in the Texas summer it runs really hot. I by-passed the factory temp gauge and went with an aftermarket direct-temp gauge.The sensor is spliced into the thermostat housing with a brass T-fitting. The temp gauge itself is attached to the side of the center console with a couple of screws. I felt that the factory gauge was inaccurate, and I wanted to know the actual, real-time temperature of the coolant. It runs 190-200 in the winter around town, but about 225-230 in the summer. Running freeway speeds in the summer, the temp drops to about 210. If I get stuck in stop-and-go traffic, it goes over 240 and wants to boil over. I have to watch the temperature closely.

I think Chrysler deliberately engineered these engines to run hot to try to lower the tailpipe emissions. The radiators aren't big enough, and the fan(s) don't drop the temp of the coolant enough in heat-stress conditions. Is there some modification that can be done to give an XJ a better ability to cool? Like maybe another radiator that is actually BIG ENOUGH to cool a 243 cu.in. engine? (Stupid car companies. They PMO.)

You can sure tell they don't expect these 4x4's to go off-road very far.

 

Have u tried a new fan clutch?