I just bought a 2016 Willy unlimited, back in May, and I love it!! However, recently I've noticed the gauge for engine heat is surpassing the normal 1/2 way mark and as it starts to rise I hear the radiator fan kick in and it turns it back to normal. The problem is that it happens pretty much constantly, the back and forth, and the fan just keeps running unless I'm at a long light or something. The radiator reservoir was low so I added some, but it really hasn't helped much. It's got 66,000 miles, so maybe a radiator flush??

 

Where is Lutz? You in a hot climate? Summer temps are a risin' and all the "my jeep is running really hot" threads are coming out, myself included. I don't suppose you have anything that you use to monitor the actual temps cept the dummy needle gauge? Your fan should kick to high around 224* +/-, and then kick back to low around 210* +/-. It's summer, so not uncommon to run a bit warmer than the rest of the year, but the fact that you are noticing the resi a bit low is a red flag. Our radiators are a common issue. The developed pin-hole leaks at the fins, often on the driver's side in the rear. You also can't usually see this as it burns off before hitting the ground. You can pressure test the radiator, but I've had a bad radiator pass several pressure tests myself. I suggest popping the air box and hose intake off, unbolting the 2 bolts that hold the radiator fan in place, and just leaning it back so you can see the back of the radiator. It takes about 15 minutes to do this. If you observe that things are in good shape, I'd suggest making sure it's burped really well and that you have no air bubbles at all in the system, then top off the resi and monitor. It's really hard just to go by "the fan is running all the time". These 3.6L engines can run a little warm in general. If you are losing a bit out of your resi over a few weeks, then it's going somewhere. If you're not losing any, then this could just be a warmer ambient temp thing over the summer. It's definitely helpful if you have a means of monitoring the actual coolant temp while driving so you can see what it's spiking up to.

 

First, thank you. Now, this may sound dumb, but you said something that peak my interest. You said to make sure it's burped really well. I opened the radiator gasket and couldn't see any fluid in the actual radiator. Is that normal or am I maybe dealing with too much air?

 

No, that isn't normal at all. When you remove the radiator cap....by the way, ONLY do this when the jeep is cold (if you don't know)...you should see coolant right there to the top. BTW, you have OAT coolant, which in a clear bottle will look purple, but when you open the rad cap will look like a dirty orange (assuming some previous owner did not change coolants) (the OAT has a purple "additive" in it and will look different in different light). I would get a gallon from the dealer (~$23). You should top off that radiator, and give the upper hose a gentle squeeze to force air out of it. Then, Check that level the next couple mornings as the heat cycles (driving) will force more air out to the top. Sometimes it takes a few cycles to get it all out. If you have air in the system, that is not helping things at all. Next question is, why is there air in the system? You have a leak somewhere.....I'd put my $5 on the radiator. It's really easy to pull that air box and tilt the fan back to get a good look at it.

 

Again, thank you! I'll do as told and let you know.

 

If you want to look at the back of the radiator here's what to do:

loosen the worm gear clamps at the throttle intake. believe an 8mm or a screwdriver
unclip the 4 clips that hold the top of the airbox down.
unbolt the 2 10mm botls that hold the intake boot to the top of the radiator shroud.
pull top of the air box, including the intake boot out. There is a vacuum hose you'll have to pull off that assembly as you lift it up
The bottom of the airbox simply pulls up with a good yank.
The two bolts that hold the fan on to the radiator are 10mm i believe and are easily accessible.
At this point you should be able to lift the fan up and lean it back. you may need to unclip the electrical connection.

If you have a leak, it will probably be pretty obvious. You'll see crusty looking coolant on the edges where the fins meet the side. If you don't see coolant here, then it's time to start looking around the engine block, and down around the oil cooler in the middle of the engine. The heater core is also a culprit, but if you're not smelling anything in the cab that is unlikely.

 

Quick update. Filled up the radiator and drove it for a bit. Never overheated and the fan didn't turn on. Symptom is fixed...now to find the leak. Thanks again!

 

Check it again in the morning. Like I mentioned, it often takes a couple cycles to get the air out. Open the rad cap when cold and squeeze that upper rad hose.

 

Google "cooling system burping" multiple videos.. recently replaced thermostat and it took 4 "Burpings" as shown over 4 days. Final "Burp" too about 20 minutes checked temp with my Jdiag it was 205 deg and the gauge was in the middle 12 o'clock high.

 

Your situation sounds very familiar to me. I just finished chasing down a coolant leak. I was motivated to do so because the Jeep started behaving like yours (temp creeping above mid point and fan whirling at high speed). Every time it did that, I found that the coolant level in the radiator was low. I would also get a faint smell of coolant at times when standing outside the Jeep. As pointed out above, you’ve got to get that air out of the system and if it reappears, then chase down the leak. The nice part about the Mopar OAT coolant is that when it dries, it has a pink/violet hue to it making it easy to spot. The easy places to look:

• Radiator cap (replaced mine on a whim and that helped a little, especially with drawing coolant back into the radiator from the recovery tank);
• Recovery tank/reservoir;
• Thermostat housing area;
• Water pump;
• Heater core (if leaking, it’s usually pretty obvious - smell coolant inside the Jeep and coolant will be pooled under the carpet on passenger side); and
• Radiator.

This thread has some helpful pics of the radiator where it can leak and what it looks like. https://www.jk-forum.com/forums/stoc...oolant-354535/ Once I went over the easy/common leak spots (twice in some instances) and eliminated them, I went after the harder culprit but more rare to occur…the engine oil cooler assembly leaking coolant. In my instance, that was where the major leak was located, causing coolant to escape and air to get into the system which allowed for overheating. The coolant never hit the ground to alert me it was leaking in there. Rather, it pooled in the V of the engine and would slowly cook off from the heat of the engine. I’m still monitoring it to see if that solved it all but so far so good.

I found buying this little OBDII bluetooth interface connector and buying the OBD JScan app allowed me to monitor the engine temps much more precisely while driving (using Trail View mode). An inexpensive item that also provides some other beneficial insights on how the Jeep is running. https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1