overheating ZJ

[JackstandJohnny]

so its kind of random.my 5.2L V8 in the  jeep runs over 100degrees now, and has the tendency to spike up a little bit more than that to.  it never comes close to redline, but it runs constant over 100.  needless to say its gettin on my nerves.  so possible problems?  there are no puddles of oil on the driveway so i doubt the head gasket is gone.   cooling system is fully charged, and the clutch fan is still good. also had the sending unit replaced a while back to, it was when the sending unit was replaced that i noticed it ran hot (had a sending unit in it before, it ran normal)  thermostat is an 190degree one, which i will swap out this weekend for a 160 degree unit.  sometime this winter i will also goto electric fan as well
anyone else point me in some direction to find out why is running warm?

[blackrube]

have your rad flushed,,,,could be plugged

[BlackYJ]

how plugged is your rad with mud?  Give it a good wash if needed

[Trouble Maker]

Best to keep the 190 t-stat, especially in the winter. Newer fuel injected engines are designed to run at a lot higher temp for max efficiency. Generally all a cooler t-stat does is make the engine run richer and once they do open they stay open and the coolant just circulates and doesn't stay in the rad long enough to cool.

 Check between the rad and ac condenser it is probably stuffed with sticks, leaves, grass and the remains of little furry forest creatures. Had my rad out was amazed by how much crap can get in there. Hard to get the junk out  without removing the rad and a pressure washer just seems to make a mess of the cooling fins. Haven't had any issues with my ZJ with the V-8 since I cleaned it all out and I run a 195 t-stat.

Do you have a winch/bumper combo that is restricting the airflow? When I mounted mine I put the winch as low between the "frame" rails as I could and cut slots in the splash pan under it for some more airflow.

You might also want to see if someone has access to an infrared temp gun (Princess Auto sells a cheap one) so you can verify that it is actually running hot and isn't just a bad sender.

[JackstandJohnny]

Black YJ, the rad should  be clean as i've only been in a mud hole or two. that being said, i am going to pull the shroud off, and the rad, see how much crap is lodged inbetween the two, cause if it is just clogged or something, the better part of my day can be spent making a mud guard or something.  i don't think its just that though, if it is i thank you guys for the tip haha.
as for a bumper in the way, no, the winch mouants into a front hitch, so it doesn't hinder air into the rad

[rws]

Try putting a trouble light in by your fan and then see if you can see the light through the front of the rad, this will tell you real quick if your rad is plugged.  You can also check your fan clutch by holding a single tissue (kleenex) in front of your rad, if the tissue dosen't move your fan clutch is not working and if the tissue gets sucked into the rad your fan clutch is doingg what it's supposed to.    X2 on what was said about changing to a lower thermostat, engine will run rich, idle speed  may increase and gas mileage will go down.

[Gearhead]

May be of little significance in this case but ,  do not use a fail safe thermostsat. It WILL fail , remaining open , when it fails . Every failsafe thermostat I've ever used has failed , they should be re-named "fail for sure" , I'll never buy another one.