Over-heating issues

Parker "P.T." JK

Parker "P.T." JK

New member
Alright, this has been going on for awhile, I've taken it to the dealership and they cant even figure whats wrong. So when I'm driving for a certain period of time, the engine will get hot, the gauge will read a little bit more than half way. It only gets hot when the AC is on. Depending on how high the fan is when the AC is on depends on how hot it will get. I've had a radiator sensor changed, thermostat changed, I've tuned the engine fans to turn on at a lower temperature, and I've flushed the cooling system. Also, sometimes when I drive around and its not overheating, coolant will come out of the its tank. I see it on my axles and on the ground, It hasn't done it in a few days, It was empty then I topped it off. It does it when I drive short distances, maybe a hose leak? But the tank is not boiling so I dont see why it would come out of the spout. Also the engine is not smoking when it gets hot. Please help. I'll try to answer questions as best as I can.
 
Have the same thing going on with my 2012 and know others experiencing the same thing too. On long hill/mountain climbs, it'll get up to 3/4. I've only had the governor kick in once while this is happening but, have never had it actually "over heat" - just get hot. I thought that a re-gear would help this out but, a friend of mine is running 5.13's and still has this problem. Sorry, no solutions here.
 
Just Throwing out a few thoughts there as I'm no expert on the JK cooling system(or any system yet) and you guys feel free to chime in if I'm off base or just plain wrong. Did the dealer run a pressure test on the system? Did they check the radiator cap? Could the tank have a crack? Is it possible your flashpak settings have something to do with it?

The only other things I could think of to check out would be the waterpump bearing for play, head gaskets, freeze plugs or maybe even the intake manifold. On my F150 the coolant enters the block via the t stat mounted to the int. manifold but dont know about the JK. If I checked all these first, I would go ahead and throw a waterpump at it because its 5 years old anyhow and because Ive run out of ideas and patience. Good luck, please post up your findings as I would like to know what to watch out for on my 08.
 
Rebel JK said:
Just Throwing out a few thoughts there as I'm no expert on the JK cooling system(or any system yet) and you guys feel free to chime in if I'm off base or just plain wrong. Did the dealer run a pressure test on the system? Did they check the radiator cap? Could the tank have a crack? Is it possible your flashpak settings have something to do with it?

The only other things I could think of to check out would be the waterpump bearing for play, head gaskets, freeze plugs or maybe even the intake manifold. On my F150 the coolant enters the block via the t stat mounted to the int. manifold but dont know about the JK. If I checked all these first, I would go ahead and throw a waterpump at it because its 5 years old anyhow and because Ive run out of ideas and patience. Good luck, please post up your findings as I would like to know what to watch out for on my 08.
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Yes they've run a pressure check and put on a new radiator cap
 
I don't even own a jk lol but I'm pretty good with a cooling system, and I have seen this first hand... At the manufacturing plant and at local mechanics, the gasket around the water pump and intake gaskets are punched out and not everytime the hole actually gets knocked out completely so when being assembled they could have missed it and the hole is open on one side and restricting the flow. Another thing people don't like to do because its not factory settings but throwing in A 160° thermostat will help alot. And do the jks have electric or manual fan? Or both? If manual or both the manual fan clutch could be weak and not cooling properly so the electric will kick in to keep it from over heating. Im just going to assume they have both since its a newer vehicle
 
Not sure if it's the some problem or not, but I put a tranny cooler on my 2010 JKUR, and that fixed the problems I was having with over heating/hot oil.
 
I have this happen on my '12 on hill climbs. At first I thought it was a problem, but now I think it's normal. I have a Bully Dog set to watch temp. My Jeep runs between 205 to 220 degrees normally. The gauge will be at the middle.

On hill climbs the gauge will go to 3/4. The Bully Dog registers at 240 degrees. The extra 20 degrees looks to kick it to 3/4. It never passes 240, holding there constantly.

I watched this on a couple of climbs going both East and Westbound in CA-120 through Yosemite.

So, I figure if it doesn't go past 240 degrees, everything is normal.

Hope that helps, or would really like to know if I'm wrong :)
 
240 isn't bad but it also isn't good. 260 cracks heads and blocks. Like I said a 160 thermostat will help it keep cool because by the time it hits 195 it is just to far to cool back down quickly when it hits 160 it will open the thermostat and help keep the flow going instead of you coolant making a lot of stop and go flows it will make longer flows to get all the cool coolant out of the radiator and flow in the hot coolant out of the block
 
billybob990 said:
240 isn't bad but it also isn't good. 260 cracks heads and blocks. Like I said a 160 thermostat will help it keep cool because by the time it hits 195 it is just to far to cool back down quickly when it hits 160 it will open the thermostat and help keep the flow going instead of you coolant making a lot of stop and go flows it will make longer flows to get all the cool coolant out of the radiator and flow in the hot coolant out of the block
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So my Jeep running at 205 to 220 isn't normal? What should be the temp? 195? It's been this way since March when I installed my Bully Dog. I've checked coolant and its at the right level in the reservoir.
 
Another very good example is the ol faithful 4.0 litre, my buddy's Cherokee was over heating a lot it had a 195 thermostat and I put a 160 in it now it runs about 180 on the highway and 195-205 on the trail. Depending on the outside temp
And like moochie said it goes into limp mode, because most of these new engine have aluminum heads and blocks and are a lot easier to crack
 
jkjurny said:
So my Jeep running at 205 to 220 isn't normal? What should be the temp? 195? It's been this way since March when I installed my Bully Dog. I've checked coolant and its at the right level in the reservoir.
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205-220 isn't bad on the trail 220 is a little high but 240 isn't good by any means. A dual cooling fan with one to kick on when it gets hot and one ran off a toggle switch to leave on all the time while on the trail will lower your temp a lot
 
The 3.6 will also go into limp mode when it it gets to a certain temp. I don't know what temp this is.
 
Ok. I hit 240 every time I climb this hill near my house. I take that route maybe 2 times a week. About a 3/4 mile climb, hitting 5,500 RPMs.

Temp will be at 240 for maybe 2 minutes max maybe not even 1 minute, but will quickly cool back down to 220 once on flat ground.

I believe I have a 10 degree difference in temp depending if the AC is on too.

I'll get the dealer to look at it too under warranty.
 
wayoflife said:
Have the same thing going on with my 2012 and know others experiencing the same thing too. On long hill/mountain climbs, it'll get up to 3/4. I've only had the governor kick in once while this is happening but, have never had it actually "over heat" - just get hot. I thought that a re-gear would help this out but, a friend of mine is running 5.13's and still has this problem. Sorry, no solutions here.
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Hmm. I'll have to check mine when I go over the summit next. I haven't noticed it overheating on the guage, but I have noticed the coolant leaking out and, as we talked about a couple of weeks ago, my fan seems to run constantly now. I'm not sure if that is different or just that I noticed it more. :thinking:
 
jkjurny said:
Ok. I hit 240 every time I climb this hill near my house. I take that route maybe 2 times a week. About a 3/4 mile climb, hitting 5,500 RPMs.

Temp will be at 240 for maybe 2 minutes max maybe not even 1 minute, but will quickly cool back down to 220 once on flat ground.

I believe I have a 10 degree difference in temp depending if the AC is on too.

I'll get the dealer to look at it too under warranty.
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The dealer may not put a 160 thermostat in it but you can ask them too, and the ac will make a difference on a smaller engine, I know its not ideal but if you have the top and doors off you can turn on the heater full blast and that will help cool it down. But NEVER turn your jeep or any vehicle off if its over heated that will raise the temp even more because there is no circulation
 
Glad to see I'm not the only one with this problem. Sad to hear that no one has a ready solution however. I took mine to the dealership just last week for this issue, he did a pressure test on it and the radiator cap failed. He replaced the cap but I haven't really had a chance to test and see if anything has changed out on the trail.
 
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