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Hmm, I've hammered up some long grades in high temps at high revs and with A/C, like Towne Pass in Death Valley, without any signs of problems. Although I don't pull trailers, I have done it with a full load of passengers and gear. No problems off road in the heat either. I don't have anything restricting my airflow though, no grill inserts and my winch/bumper are low.
 

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Haven't done a test yet but I believe that removing the air dam is a big contributing factor to hot Jk's. The air dam creates a low pressure area that helps pull air through the radiator. Look at the number of vehicles that have some form of air dam. All below the radiator. When you drive at speed that forces the air to the side or down creating a low pressure area that the air flowing through the radiator fills. That gives increased air flow through the radiator and therefore better cooling.
 

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Get rid of the grill inserts.

You can add hood vents that will also help.

You can also add a product like Water Wetter to your coolant that is supposed to reduce operating temps.

When it gets hot turn off the A/C and turn on your heater full blast.
 

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Mine will creep up to 3/4 on grades so I removed my grill inserts. No change in temps.

I too have a higher.mounted winch (VR10K on a PSC brawler lite).

Since it's never put me onto limp mode I just deal with mine as is. Brought it in to the dealer with heat complaints and they found the passenger head running 60* hotter than the driver side. Replaced both heads, no change.
 

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Not with the radiator sitting behind the AC condenser and transmission cooler, no.

They are just ornaments masquerading as useful.

Mark

Sent from my SM-G935V using Tapatalk
 

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Haven't done a test yet but I believe that removing the air dam is a big contributing factor to hot Jk's. The air dam creates a low pressure area that helps pull air through the radiator. Look at the number of vehicles that have some form of air dam. All below the radiator. When you drive at speed that forces the air to the side or down creating a low pressure area that the air flowing through the radiator fills. That gives increased air flow through the radiator and therefore better cooling.
^^^Bingo..many don't understand this. Also remove your engine cover, and keep your radiator flushed out externally.

I live in hot as hell Phoenix az. And do not run these high coolant temperatures that many of you have mentioned. Plus I do drive in our mountain areas, but do not tow trailers.
 

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2014 Rubicon w/4.10, 34" tires and a winch dead in front of the grill... I live in Arizona and have never overheated on or off-road, and even use the A/C off road in some circumstances. I'm not 'unaware of it', it simply doesn't overheat (on warm days I usually monitor coolant and trans temp when off road.) I do see temps in the 220-225 range but that's because the JK doesn't turn the fan on until these temps (or at least doesn't spin it fast enough to hear, it's variable-speed.) But once the fan comes on coolant temp is controlled.

That's not to say that it's impossible to overheat, just that it doesn't happen to me (and apparently several others in the thread) and if I overheated every time I went offroad personally I'd be looking for a problem, and in the OP's case (overheated on a 80F day and then everything seemed normal) I'd probably be checking the thermostat because yes, the prediction above was right, I'm saying that common severe overheating of a JK cooling system in good working order is not normal.
 

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I wish I could find a jk in my area that didn’t overheat. I would like to see what they are doing different. Every 3.6 jk I have been in, that is a half dozen, has seen 235-245 temps off road or on long uphills. Then on here people say that theirs doesn’t. I am around 3 jkurs in hunting season every year, so not during high temp times. Every one of them the temp needle starts to climb in 4lo driving into a back country spot And every one of them I can hear the fan kick on when we stop to glass an area and leave it running. So that is 226 just sitting still at an air temp in the 40’s. My fan turns on in stop a go traffic when it is single digits temp out side. Gauge doesn’t budge until 235. So if you see anything other than dead nuts center you are 10 degrees from a warning. I would be surprised if everyone says they haven’t needle seen the needle go past center. To me 235-240 is overheating. Any time the fan is over come in cooling capability and you have to alter what you are doing that is overheating. Maybe what others are saying is limp mode or a CEL indicates over heating and that is the difference.
 

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I wish I could find a jk in my area that didn’t overheat. I would like to see what they are doing different. Every 3.6 jk I have been in, that is a half dozen, has seen 235-245 temps off road or on long uphills. Then on here people say that theirs doesn’t. I am around 3 jkurs in hunting season every year, so not during high temp times. Every one of them the temp needle starts to climb in 4lo driving into a back country spot And every one of them I can hear the fan kick on when we stop to glass an area and leave it running. So that is 226 just sitting still at an air temp in the 40’s. My fan turns on in stop a go traffic when it is single digits temp out side.

Gauge doesn’t budge until 235. So if you see anything other than dead nuts center you are 10 degrees from a warning. I would be surprised if everyone says they haven’t seen the needle go past center. To me 235-240 is overheating. Any time the fan is over come in cooling capability and you have to alter what you are doing that is overheating. Maybe what others are saying is limp mode or a CEL indicates over heating and that is the difference.
 

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Replaced radiator. Replaced thermostat. Replaced temp sensor. Replaced fan. Flushed system. New hoses. Have 4.88, 315 70r17. 3.6 l. Low mounted winch that blocks the air a little but not more than 10%. Hood vents, 3. No air dam. On the TD2 see temps of 245 or higher on long grades. OAT can be 40 or 90+. Off road never have a problem just on the highway. Don't know what to do next.
 

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Mine has been that way since day one, doesn’t matter if it’s 60F or 110F outside, it will hit 230 to 235 in city driving. That tells me the issue doesn’t lie in the cooling system by itself, but in the programming. I suspect that the lower temperature Jeeps must be running a different thermostat in conjunction with a different program.
 

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I think that weight plays a part in this. Example: My Grandson's JKUHR is 600 lbs. Heavier than my JKR. Plus I have removed the rear seat, which is another 72 lbs.
 

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I've got to admit I'm a little bit surprised by the overheating issues. Owning a 2012 JKUR and wheeling with lots of people driving 2012+ I've never seen an overheating issue. I have heard of the Hot Oil trans warning many times. My 2012 is bone stock with around 65k miles and has never overheated.
 

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That's not his radiator. It does appear he was driving a tad close to the vehicle in front, though.

Do what you want, and make your junk as pretty as you like. The OP should, and sounds like has, ditched an unnecessary cover improve his cooling situation.

Mark

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Never said it was, but with insert, that would have been nowhere near as bad. As for unnecessary, that's your opinion. If they were, automakers wouldn't put them on vehicles.

As for me driving "junk" I won't even comment on that.
 

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If grill inserts are such a big problem why did engineers but one on the JT? Considering the cooling system is the limiting factor in towing capacity. Here's an article about the engineering of the JT cooling system that may provide some insight. From my experience with my JKU the grill insert didn't seem to make any significant difference.

https://apple.news/A25uvUeFXSWKCAJNtRkGLfA

 

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I think there are 2 conditions being talked about. First is a warning light or limp mode second is 235-240 temps on the eivc. 240 the gauge has just started to move and if you continue to climb whatever grade you are on the 3.6 has no further capability to cool the coolant and will get hotter till limp mode. This condition is easy the do here in mountainous terrain. I would guess anyone could anywhere but it almost will never happen. It is common for the 3.6 to need to be in 3rd gear (auto) to climb a hill and going 65-70, speed limit and slower than traffic. If you do that for a mile or 2 your 3.6 will be 240+. I have a 6sp, so no hot trans oil message. But at 230 I pull into the slow lane and slow down to typically dangerously slower than posted limits. I will sometimes push it if close to the top of the hill. Many will say this is extreme, those people don’t live here. I see JKs blow past me and I shake my head. My buddy with a 2015 said he also did have a problem until we were headed up together and I called him a told him to check his eivc and he was at 241... he shit purple kitty cats... now he watches it also and it is exactly the same as mine.

I believe all 3.6s do this, but conditions everywhere are different.
 
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