Well I went and did a little wheeling yesterday and after climbing a rocky hill I started to over heat, I have an auto and right away thoughts came to the talk of autos over heating that I've seen on here, one problem though another jk with me has 6spd and was over heating also, both cooled down after idle with the heat on high for about 10min...we were ok the next cpl of hours...On my my home on the highway I began to overheat and had to drive home with the heat cranked, the manual also over heated today.....we both cleaned our engines and radiator wasnt muddy just dirty and hosed off.

Fans working also....Anyone have any idea what could be causing it?

 

Are you sure your raditor is total clean. I been in the New Jersery muck alot with my old TJ. I had to remove my radiator to get all the mud out before. The radiator can look clean on the outside and still have mud caked in the fins.

 

and double check your radiator fan.. Park your Jeep, turn on your ac, and open your hood. It should kick on. I got my radiator fan accembly and its motor replaced under warranty, as it burn out..... Had the same problem, but with a manual.

 

run water through the radiator from the inside out...

Also, water should come through the radiator at all locations... on my offroad rig i have to clean the radiator every couple months or so

 

if you open your hood there will be a plastic strip that run across the top of the radiator area... pull this off and look down in the gap. It is probably caked with crud/leaves/mud/ etc. Even if the the front looks clean, stuff get up and behind it.


Forgive the lingo:
There are two "cooling plates". the front one is black and visilble from the outside. I believe this is what cools the AC... behind that, and not visible from the outside, is a silver (aluminum) one (i think to be the radiator). Pull off the plastic trim piece (4 plastic pins hold it in place... may be a bit tough but the pins are reusable if you pull straight up)... and if it look nasty down there, hose it off.

If that does not do it or it is not dirty, take it in...post back!

 

Hey Tom check out this link about my radiator install
https://www.jk-forum.com/forums/modified-jk-tech-2/griffin-radiator-35612/

If you ever got it real muddy, I would just suggest taking the fan out of the jeep, its only 2 bolts one each side on the top and you can keep the overfill tank attached to the fan shroud, just pull the hose off the radiator and leave it clippd in there, also unplug the fan wiring. Once you do that you can get the hose on the radiator good. If you dont you'll just be getting it thru the fan blades and only cleaning the center. Taking the plastic that covers the top between the radiator and black ac condensor will help you get some water down in front of it too. Best thing though is take hose without nozzle on it and hold it pretty close to the radiator and wait till the water is passing thru it that way you know that area is clean. Even with my radiator out of jeep I cleaned it for 20-30min to get it as clean as I could. JUst dont use high nozzle pressure to clean the rad it will bend the cooling fins. I tried cleaning mine thru the front and thru the fan blades(with engine off) 4 times before I gave in and bought a new rad. I think you will be fine if you clean it good like I said though.

Wait till you see the pics of my stock one out of the jeep

Any questions let me know

Edit.....once you unbolt the fan you can lift it straight up, the bottom is just sitting in v-groves
Tim

 

another possibility could be a defective thermostat but unlikely on such a new vehicle

 

nah we've wheeling in some of the same mud lol....I had the exact samething happening and had to run with the heat on....did u see the pics of my rad?

 

Just now looked at the pics lol, yeah im sure that is definately not helping the situation, hope you get it back under control. My 78 CJ-5 used to overheat occasionally and stopping to let things cool is just a pain

 

Overheating = temp gage in red, and/or boiling in overflow/catch tank. It sounds like the OP really had overheating.

The "3/4 mark" behaviour is normal because the electric fan is about to come on. You can see temps a bit over 3/4 if you get out and shut it off just before the fan is about to run. Still normal.

You can check your electric radiator cooling fan operation by starting the engine and running the AC. The same two outputs from the TIPM control the fan's two relays, thus controlling the two speeds. Running the AC should be a reasonable indicator that the fan system is working, accepting the small possibility that one speed could work and the other may not.

The temp signal is from the CTC, and tells the TIPM, PCM, and ultimately the instrument cluster about the coolant temp. Barring any aberrations in the gage the temp on the dash is the same as the computers sees. According to my scan gage the t-stat control temp is 188 degrees F. With normal idling and low speed operation off road I have seen 227 degrees F. 40 degrees F represents quite a bit of swing on the gage from the normal place it sits when at speed, and when I am off road.

+12 or whatever the count is on mud and dirt blocking air flow. A sure sign that this is the case is a climbing gauge for more than 30 seconds after the fan is on, or at sustained road speeds over 20 MPH.