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Discussion Starter #1
Basically Since I bought my 2012 Wrangler last year I've had overheating issues or atleast I thought I did.
I made a thread on here, I looked at other forums and posts and never got any solid information. At first I thought it was due to my winch and grille inserts. But I was told by other people they run high mounted winches and live in hot weather areas and never have a problem.

Long story short I've discovered that chrysler "designed" our wranglers with the 3.6l to run hot for emissions. Thermostat will open around 221 degrees and the fan wont kick on to high speed until 230 degrees, which falls in line with the temps I've been seeing.
It also seems although they couldn't get proof that the temp gauges in the newer Wranglers are the same as the ones in the 3.8l JKs and they should have been calibrated differently so the needle doesn't go so far over at lower temps than what the engine is designed to run at.

Honestly I think this is BS. this quote about the heads going bad makes me question everything.
Bob Lee, Chrysler's chief of engineering, said, however, that excessive heat was not a factor in the malfunction and that his engineering teams spent months isolating its causes. He said the malfunctions were the result of "an interaction of a lot of rare things that ultimately come together to affect a small percentage of the population." Those could include different fuel mixes and the way the vehicle is driven, he said
I just don't see how a v6 with aluminum heads designed by chrysler is not taking damage running so hot. I love Jeeps and I'm a mopar fan in general but Its not like they're known for high quality products. I do think they couldn't design a better way to run cooler and still beat emissions without added cost so they said "eh good enough"

With all of that said what are some suggestions on how to keep temps down on my jeep. I managed to get to 234 degrees today and the outside temp was only 43F. At this rate when its 80-90 degrees out my jeep will be idling at 230.

I haven't found a lower temp thermostat for the jeep yet but some people argue that won't help anyway.
I've seen people install mechanical fans on their JKs, hood vents, better fans, dual fans, tuners to change temp that the fans come on, mechnical bypass switches etc etc.
 

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I was having the same issues until I installed @TOTL Innovations hood and have not had a problem since.

Wheeling in Idaho in the summer gets warm. The other Rubicons I run with all went different directions (only in hopes to write a blog someday on different products):

  • Crawler Concepts hood cutout (one with Poison Spider)
  • AEV Hood
  • MV8 hood
  • no inner fenders
  • all stock
The stock Rubicon is the only one that gets really hot.

Jeep's engine, and cooling system are not bad...just got to let the heat out.
 

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I ripped out the front fender liners, put on hood louvers added a spal fan in place of stock fan and use the diablo tuner to turn on the fan at 195 and it kicks into high at 205.

In the summer time wheeling in 110 degrees it might top out at 210 degrees. But going up long hills it will break into the 220's.


Check around and see what other programmers let you adjust the temp for the fan to come on at.
 

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And remove the grill mesh inserts, I know ppl run them but they will block air flow. Take them out see if it makes a difference if it doesn't put them back in, you can pop the grill off in what 10 mins?
 

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Discussion Starter #5
And remove the grill mesh inserts, I know ppl run them but they will block air flow. Take them out see if it makes a difference if it doesn't put them back in, you can pop the grill off in what 10 mins?
If I run no winch cover and no grille insert it does keep it decently cooler, and I will be doing that in the summer time but on days when its 60-70 degrees out and raining, I don't like to run without a cover for my winch so I still have issues getting hot. I did buy a more "form fitting" cover so that should help.
 

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If I run no winch cover and no grille insert it does keep it decently cooler, and I will be doing that in the summer time but on days when its 60-70 degrees out and raining, I don't like to run without a cover for my winch. I did buy a more "form fitting" cover so that should help.
Unless you have a potato sack or even a potatoe sack on your winch I would bet the inserts are doing much more harm than the cover. :wink2:
 

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I ripped out the front fender liners, put on hood louvers added a spal fan in place of stock fan and use the diablo tuner to turn on the fan at 195 and it kicks into high at 205.

In the summer time wheeling in 110 degrees it might top out at 210 degrees. But going up long hills it will break into the 220's.


Check around and see what other programmers let you adjust the temp for the fan to come on at.
^X2 on Gunny's input.
I got a four door from the year prior to yours ( manufacture date of 11/2011) & while it is not your 3.6l pentastar, still thought input might be helpful like USMC's .
I could tell after 2 weeks of ownership and one tow across town that better cooling was gonna be imperative so the first order of business was an auto tranny cooler for slightly larger GVW than I would ever require from B&M , 14" hood louvres from Synergy and a FlashPaq to control when the fan kicked-on temp-wise. I also trimmed fender liners but did not fully remove. The heat exhausted from the louvers blew me away for first few weeks ; i could see and feel it vacating the engine bay .

Late Summers in the mid-South remain stupid hot. I have upgraded to a Spal fan as well as an aluminum shroud , set the fan to kick on "low" at 195 F , 205 degrees F "med" and 215F "high" increments via the tuner.

e.g.-I ran a very hard day offload last Oct when it was still boiling hot outside ; after 6 solid hours of idling and crawling in the sun in the black Jeep, this is the Torque Pro read-out for my temps from that afternoon , this after driving home 75 miles just before I shut her down so I could check the temps.
I do not think I have seen temps above 197 degrees for the coolant on the hottest of days. the louvers directly over the exhaust manifolds together with the big Spal fan (and an 18psi rad cap) seem to be more than ample for keeping this 3.8l cool.
[/COLOR]
 

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Discussion Starter #8
Unless you have a potato sack or even a potatoe sack on your winch I would bet the inserts are doing much more harm than the cover. :wink2:
If I remember correctly I did check temps after each and didn't notice much of a difference with the inserts but I don't remember and I'd imagine they are blocking a decent amount.


The winch cover is larger than needed (which is odd because thats what was recommended for my winch) and its rather rigid. As you can see from the picture its pretty close to half way up on the openings so I'd say it covers maybe 40% of the 7 slots.
 

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Discussion Starter #9
^X2 on Gunny's input.
I got a four door from the year prior to yours ( manufacture date of 11/2011) & while it is not your 3.6l pentastar, still thought input might be helpful like USMC's .
I could tell after 2 weeks of ownership and one tow across town that better cooling was gonna be imperative so the first order of business was an auto tranny cooler for slightly larger GVW than I would ever require from B&M , 14" hood louvres from Synergy and a FlashPaq to control when the fan kicked-on temp-wise. I also trimmed fender liners but did not fully remove. The heat exhausted from the louvers blew me away for first few weeks ; i could see and feel it vacating the engine bay .

Late Summers in the mid-South remain stupid hot. I have upgraded to a Spal fan as well as an aluminum shroud , set the fan to kick on "low" at 195 F , 205 degrees F "med" and 215F "high" increments via the tuner.

e.g.-I ran a very hard day offload last Oct when it was still boiling hot outside ; after 6 solid hours of idling and crawling in the sun in the black Jeep, this is the Torque Pro read-out for my temps from that afternoon , this after driving home 75 miles just before I shut her down so I could check the temps.
I do not think I have seen temps above 197 degrees for the coolant on the hottest of days. the louvers directly over the exhaust manifolds together with the big Spal fan (and an 18psi rad cap) seem to be more than ample for keeping this 3.8l cool.
[/COLOR]
Thats the issue im annoyed with. You spent what? $1000+ to fix a factory defect? Thats BS if you ask me.
 

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Discussion Starter #10
so I put the slimmer winch cover on and removed the grille inserts. I still hit 230 degrees today but managed to go as low as 188 degrees afterwards.

outside temp was still only 45 degrees so I'm not sure what I will do come summer. Next week is supposed to get close to 80.
 

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so I put the slimmer winch cover on and removed the grille inserts. I still hit 230 degrees today but managed to go as low as 188 degrees afterwards.

outside temp was still only 45 degrees so I'm not sure what I will do come summer. Next week is supposed to get close to 80.
programmer and louvers and a spal fan. Does it suck spending all this money? Sometimes, just look at it as upgrades to your jeep.
 
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Thats the issue im annoyed with. You spent what? $1000+ to fix a factory defect? Thats BS if you ask me.

It's been a good 3 or 4 years - I honestly have never really tallied anything spent on this $$$ vacuum or it's likely to cause my eyes to shrivel up or my head explode.
But, you prompted me o ballpark the math and simultaneously recall why that is never a good idea ; I find that all those initial parts I mentioned actually do ( collectively)add up to around a grand.

Damn-It!

I am shifting to denial and no longer wanna ponder total investments made in the JKU. :puke:

I can tell you I have spent more on the XJ than the JKU at this point . To be fair it has been here since '95, so not really a fair comparison.


ok, Mr. @mvjeeper, good point; Now I am pi$$ed !

hahaha:wink_animate:


I recommend not doing this very often.
IOWs, don't add $tuff up; just replace to make better but know that you can certainly leave it stock and have major fun with it, too. :jeep2: (edit: take a look at this and some waterproofing with silicon and fluidfilm for warmer months , maybe? )

 

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Discussion Starter #13
I took the new winch cover off today before going to work and just ran without one, my temps were lower across the board. Granted outside was anywhere from 4-6 degrees cooler than yesterday's drive but the highest temp I hit was 212. I stayed under 200 even without my heat on for most of the drive.
 

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Discussion Starter #14
It's been a good 3 or 4 years - I honestly have never really tallied anything spent on this $$$ vacuum or it's likely to cause my eyes to shrivel up or my head explode.
But, you prompted me o ballpark the math and simultaneously recall why that is never a good idea ; I find that all those initial parts I mentioned actually do ( collectively)add up to around a grand.

Damn-It!

I am shifting to denial and no longer wanna ponder total investments made in the JKU. :puke:

I can tell you I have spent more on the XJ than the JKU at this point . To be fair it has been here since '95, so not really a fair comparison.


ok, Mr. @mvjeeper, good point; Now I am pi$$ed !

hahaha:wink_animate:


I recommend not doing this very often.
IOWs, don't add $tuff up; just replace to make better but know that you can certainly leave it stock and have major fun with it, too. :jeep2: (edit: take a look at this and some waterproofing with silicon and fluidfilm for warmer months , maybe? )
LOL as long as your wife doesn't see the amount then its all good.
I don't mind spending money on my Jeep. I'm tempted to spend 3 grand just to upgrade my gearing when really I don't need to.
BUT to spend all this money to fix a factory defect, thats not cool.

Also I did find that mishimoto does make a lower temp thermostat but the threads I found talking about it mentioned how they'd never throw a lower temp thermostat into their jeep because thats not what it is designed to run with.
But keep in mind all the head issues the 3.6l has, they were all "designed" to run how they are and its basically not an IF we start burning oil but WHEN. and its usually well before a normal engine would.
 

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I went thru the same issues with my JKUR. I was seeing the same temps and even a bit more than you. The dealer even replaced the water pump under warranty, to no avail. I finally just resigned myself that it was operating exactly as it was designed to operate.

I know you want to think of this as a defect, but I don't think we can be so sure of that. Here are a couple of things to consider. Robbie at Motech actually prefers the Pentastar fan to help keep his LS and Gen V conversions running cool. So we know the 2012+ JKs certainly CAN run cooler if they need to. Yet they were designed to run at the temps they run. Must have been a reason.

I was just reading in a car magazine that some new car, forget which one, actually has a split cooling system. The heads run at 195 degrees and the block runs at 220 degrees. The reason they did this is they wanted the oil to be hotter and the exhaust gas temps to be lower. By having lower exhaust gas temps they were able to run 20% exhaust gas in the cylinder on the compression stroke rather than the normal 10%. Believe it or not, this actually increased fuel economy by 5 to 6%.

And although it was not mentioned in THIS article I have read about engines that require a hotter oil to better lubricate the bearings and journals. The tolerances today are so much tighter that cooler, thicker oil was not doing the best job.

My point is that these new engines and control systems are far too complex to apply simple old school thinking to. Yeah, to you and me, running at engine at 230+ degrees is a recipe for disaster. But we are not talking about a 1967 L88 427 here.
 

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Discussion Starter #16
I went thru the same issues with my JKUR. I was seeing the same temps and even a bit more than you. The dealer even replaced the water pump under warranty, to no avail. I finally just resigned myself that it was operating exactly as it was designed to operate.

I know you want to think of this as a defect, but I don't think we can be so sure of that. Here are a couple of things to consider. Robbie at Motech actually prefers the Pentastar fan to help keep his LS and Gen V conversions running cool. So we know the 2012+ JKs certainly CAN run cooler if they need to. Yet they were designed to run at the temps they run. Must have been a reason.

I was just reading in a car magazine that some new car, forget which one, actually has a split cooling system. The heads run at 195 degrees and the block runs at 220 degrees. The reason they did this is they wanted the oil to be hotter and the exhaust gas temps to be lower. By having lower exhaust gas temps they were able to run 20% exhaust gas in the cylinder on the compression stroke rather than the normal 10%. Believe it or not, this actually increased fuel economy by 5 to 6%.

And although it was not mentioned in THIS article I have read about engines that require a hotter oil to better lubricate the bearings and journals. The tolerances today are so much tighter that cooler, thicker oil was not doing the best job.

My point is that these new engines and control systems are far too complex to apply simple old school thinking to. Yeah, to you and me, running at engine at 230+ degrees is a recipe for disaster. But we are not talking about a 1967 L88 427 here.
Parts I agree with parts I dont. Yea it is a new modern engine but its made by chrysler and they don't exactly have a good record of reliability, just look at the issues the 3.6 have already. And yes we can say it was "designed" to run that hot but theres no proof that its the actual case. For all we know it could be a cost savings thing. Theres plenty of cases form all different brands of companies cutting corners to fix an issue. Look at VW with their diesels.
 

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Parts I agree with parts I dont. Yea it is a new modern engine but its made by chrysler and they don't exactly have a good record of reliability, just look at the issues the 3.6 have already. And yes we can say it was "designed" to run that hot but theres no proof that its the actual case. For all we know it could be a cost savings thing. Theres plenty of cases form all different brands of companies cutting corners to fix an issue. Look at VW with their diesels.
I agree with you that FCA builds some really shitty products. Personally, I would never own one except for a Jeep that is used for off road travels. When people ask me if I think they should but a Jeep, I ask them if they plan to wheel it. If the answer is no, I encourage them to buy something else. If you aren't going off road with it, there are FAR better vehicles than a Jeep!!

It could be a cost savings thing but unlikely. The software controls when the fan comes on and at what duty cycle. Now maybe they were trying to prevent warranty claims by running the fan motor less often, but that seems like a stretch.

As much as you and I don't trust FCA to know what the hell they are doing, in this case, what choice do we have??
 

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Discussion Starter #18
I agree with you that FCA builds some really shitty products. Personally, I would never own one except for a Jeep that is used for off road travels. When people ask me if I think they should but a Jeep, I ask them if they plan to wheel it. If the answer is no, I encourage them to buy something else. If you aren't going off road with it, there are FAR better vehicles than a Jeep!!

It could be a cost savings thing but unlikely. The software controls when the fan comes on and at what duty cycle. Now maybe they were trying to prevent warranty claims by running the fan motor less often, but that seems like a stretch.

As much as you and I don't trust FCA to know what the hell they are doing, in this case, what choice do we have??
Well we can spend over 1k to fix it lol.
 
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