Well since i bought mine it has run at 210 to 220 and always up and down .
I was under it yesterday messing with the cooler hoses when i noticed the eletric fan housing clips on the bottom had broke off pushing the fan out about an inch or so.
I drill a hole and zip tied it back in place and checked the temp
low and behold it is now about 190 and staying there.
so if yours is doing the same thing you might want to check it out.

 

Now you are running a little cool. Normal operating temp for the 4.0 is 210deg.

 

Fan shroud being in place and intact is very important as well as all other components of the cooling system being in top notch condition. I suspect overheat threads will increase considerably in numbers over the next 6-8 weeks. Always do on most old car forums.

 

Hope you plan on putting in more time on the forum, they're going to need you

 

Unless you have an aftermarket gauge you wont ever know for sure what temp your at.

The gauges are not that accurate.

 

Thanks........I just wish more folks would read my sig. The hood is an inspection cover, not a beauty cover.

 

Since normal temp is 210, does running at a lower temp have any negative effects?

 

If it's running at considerably lower temperatures, it'll run rich. There are a few more things but I can't remember what they are off the top of head.

 

FWIW, the needle of the factory gauge pointing to +/- the middle is normal. Nowhere in the FSM does it say 210F is normal operating temp. It does say at 160F a normal heat/warm-up cycle is counted by the ECM and at 218F the ECM turns on the efan. In freezing cold weather, running the heater, it won't run 210 just like in 100 degree weather, running a/c, while stuck in traffic it won't run 210 but as long as coolant temps are within normal parameters, the factory needle is rigged to point +/-middle of the gauge as do most other factory temp gauges.

 

reason i ask is that my jeep was running hot, so i flushed the cooling system and had to take a look at the thermostat, after i got into it i saw that it wasnt frozen up but was covered with junk, so i just took it out and left it out, now its running at about 150-160 degrees, another concern that i had is that the plug going into the thermo sending unit does not get power on either side, is this supposed to happen? and if not, is there a fuse or something that i can check?

 

The sensor in the t-stat cover signals the ECU, I'm surprised u don't have a check engine light.

 

i did have a check engine until i took the thermo out, do you know what the possible cause of that plug not getting power could be?

 

Might need to pull out the ol' volt/ohm meter and start tracing back from the connector. The factory default is "efan on" when the connector is removed from the sensor and sets a CEL.

 

Well it is alway at the 210 and goes up when i go threw drive threw
now that i put fan housing closer it is under the 210 and stays there.
It has good fluid and have flushed it good and is a good green color.
i just wanted to share just incase someone else may have this and not looked at bottom of housing to see if it is flush. You never know.

 

I just went out and checked my fan and everything is fine. Not trying to thread jack but seems like your problem is cured. I bought the jeep without the temp gauge working. Just put a new sensor in to make the temp gauge work and a new sensor that makes the electric fan go on. Now that I have a working stock temp gauge its shows it's running really hot. I was going to install a mechanical temp gauge and wire up a toggle for the fan to turn on and off when I want it. Ate those good ideas?