Im thinking I am going to go get a tstat from jeep myself.

I run the Stant Superstat 195 and every single time I start my jeep for its first warm up of the day the temp will go up to 213-215 then drop back down to 195-206. For whatever reason the Superstat just cannot keep the temps even enough for my liking in my jeep. Keep in mind its been in the 40s since November. I also have a digi therm gauge so maybe It just is a little more sensative to small quick temp changes than the regular gauge.

My reg gauge will go up to the 210 mark or just a hair past while the digi reads 215.

Pain in the neck as everything freaks me out with coolant temps lol.

 

My '95 XJ 4.0 has an engine out of a '03 XJ. This engine runs way hot, 210+ all summer, and if I get stuck in traffic I have to watch it closely to be sure it doesn't boil over. Rolling down the street without stop-and-go traffic, in the summer, it runs around 200. If I run the a/c, it overheats. It has an aftermarket 210 thermostat. I tried several different temps, trying to figure out some way to get it to run cooler.

I think Jeep engineered these engines to run hot, trying to bring the tailpipe emissions down, but all they did was create a PITA. It has new radiator, new hoses, new water pump. Are there any radiator swaps that can cool it off better?

 

No XJ's built after 2001. Maybe in china? but not here.

Have you looked at your mech fan? May need to replace the fan clutch.

 

My bust--you're right, of course. The guy I bought it from told me it was out of an '03, but he didn't say what. Maybe some other model Jeep. Any other models in '03 have the 4.0 L as an option? Maybe it's out of a Wrangler.

 

I thought the grands went to the 3.7 v6 in 2002? Probably out of a wrangler.

Seriously though, check your mech fan clutch. Its easy to do and from what I have read on here your symptoms seem to be a good indicator that your fan clutch is weak.

Im going to switch to a ZJ fan clutch this spring when I can go to the JY without freezing my **** off.

 

....a 210 t-stat?????? Since the t-stat controls minimum coolant temp, may want to drop back a little.