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Discussion Starter · #1 ·
Hello guys iam new here,
My JK temperature gauge goes above the middle when going uphill for long time before the fan turns on and the temperature returns to the middle.

is that safe and normal?
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My 14 has done this from day 1. I think my fan does not kick in at the correct temp but dealer says no way to adjust.
 
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Normal - my 13 JK fan comes on at 226*, one hill near my house will take it up to 3/4 of the gauge and ~242* if I keep RPM's up near 4000-4500 (35's w/ 4.56). Once I crest the hill and back into higher gear it drops right back to 220'ish.
 
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That's now too bad. As long as it doesn't go past the 3/4 mark you're fine. Mine routinely gets to 230F on hills.
 
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How old is the rig? When is the last time, if ever, you flushed the cooling system?
 

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Welcome to the forum. JKs generally run hot. What you show in the pic would not panic me but I would keep an eye on it. It is helpful to know what year, model, etc and just how big is the hill.
 

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Discussion Starter · #8 ·
People get nervous about that, and it is a lot of the reason modern gouges are usually little more than idiot lights in the more boring cars. They program them to sit dead nuts in the middle because people panic when they see it working like an actual gauge.
well, that is a convincing answer. thanks.
 

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Discussion Starter · #9 ·
Welcome to the forum. JKs generally run hot. What you show in the pic would not panic me but I would keep an eye on it. It is helpful to know what year, model, etc and just how big is the hill.
it is a sahara 2017.
the hill is about 20 min going up in about an average of angle 30 degree
 

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Welcome to the Forum, from Cave Creek AZ.
Anything over 230, I would have some concern. I live in Arizona, very hot in mid Summer. I have pulled some long steep grades in our mountains, and have seen temps in the upper 220’s. But mine is a two door, so less weight, plus I have nothing blocking the CFM air flow to my Radiator. I also keep the bugs washed out of the Radiator externally.
 
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If more than 50 or 60k miles, I'd flush radiator and while at it, repalce the thermostat simply as a consumable part. Beats having it fail in 10-20k miles and having to do all of it over again. Cheap insurance.
 
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We have gone up some step mountain passes, in some pretty high heat. And unless we are towing something heavy it never does that.
I would first make sure externally the radiator is not clogged with mud. Ours did end up fairly well clogged with mud.
I would also check and / or replace the thermostat.
If still running hot, make sure the cooling system isn't clogged internally.
What gearing and size tires. Tall gearing and / or large tires can contribute to higher temps under load.
We did end up upgrading to a larger radiator, but only because we tow a heavy RV trailer in the mountains. That was when I saw how clogged our stock radiator was.
I think the stock cooling system is just barely large enough for the JK. But it should be able to limit temps to around halfway up the gauge. But it doesn't take much to upset that and run hot.
 

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The factory designed the Jeep thinking to run that hot. Our fan won't start cooling down our system until the coolant temp is > 223F, it starts at low speed and you can hear it at around 225-226F when the fan speed is ramping up Most people won't notice the high temps because they don't look into the actual coolant temp value until they see a DTC or like in your OP the gauge moving past 1/2 mark and they will try to find about what might be going on there.

My 18 JKU will reach 229-230F stock going up a 3-4 mile strech but my gauge wouldn't move from the 1/2 mark. That's with 32k miles on the odometer. My 13 did exactly the same on the same uphill. Can't tell you what coolant temp is needed to move the needle past the 1/2 mark though but if i remember is 236 or so from reading other posts around? i've never ever saw such high temps that doesn't mean it's not possible just perhaps the hills were not aggressive to grant such high temps and in my case i tuned my fan early on the moment i saw >220F going up. after tunning, i have yet to see anything higher than 219F, same uphills.

As far as solutions go, You can live with it and look the other way and deal with it the way others do slowing down in the hill or give the thing a rest etc depending on the circumstances of the hill/speed etc etc.. You can also go at it doing a coolant flush and since you're there a new T, if the rad was clogged up with mud because you like to play in that stuff that's another reason to keep keep it clean as much as you can.
You can also spend money on a new more HD/bigger alum radiator and a secondary fan with a manual switch.
You can also use jscan and turn the fan on for the couple of min they allow you to run it
You can grab Hptuners or anything that allows you to tune your FAN calibration, and tune the fan logic to start the fan cycle sooner.
The sky is the limit pick whatever works for you. Personally i've tuned the fan in literally every single vehicle i've had without a single adversed effect. With the Jeep the results speak for themselves in my case since this is the only application i've had where i've seen these crazy high coolant temps. I've shown videos here of the behavior after tune in the JK and also exactly what to do with Hptuners to address this silly issue. Will work the same in the JL's too. Same fan logic. I haven't seen the JT logic yet so i can't say if it's the same, i'd venture to say it prob is..

Good luck.
 
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I think people forget just how heavy our rigs have gotten over the years. The JK put on almost 1000 lbs of weight vs the TJ. But there is only a small increase in engine torque out from [email protected] vs [email protected] And torque is what gets us up the hill. @rsmwrangler pointed out some of the ways to run cooler. I will add to that and say watch your engine load. The higher the load the hotter you are going to run. How can you watch your engine load, if you have the pedal to the floor and you are not accelerating you are at 100% engine load. Better to drop a gear and slow down a little. If I attempt to run the pass by house in 6th gear all the happens is I slow down (can't maintain speed limit) and the temps climb. If I drop it to 5th, 3200 rpms I'm running the speed limit and temps are below 210 even on high 90 days.

Of course you could swap in a V8 and all your problems would be solved.
 
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it is a sahara 2017.
the hill is about 20 min going up in about an average of angle 30 degree
Well that's quite an incline, no wonder the temps get up.

As stated in a previous answer many of the modern (temp) gauges are programmed so, that as long as the engine runs within normal operating temperature range, the needle is dead centered. My previous VAG-group cars did this.

Wranglers have an honest temp gauge, so whater the temp is, that's what the gauge reads instead of the scale being "bipolar", displaying only things being ok or not ok. This helps with staying on top of things: when you see the needle hiking upwards you can react if it will not settle.
 

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the hill is about 20 min going up in about an average of angle 30 degree
That’s a pretty intense incline, what gear are you in and how fast are you going?
 

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hkh003 - since you have the Sahara, you should have the evic which will display a lot of info. Use the menu button to toggle to Vehicle Information then use the down arrow to find Coolant Temperature. This displays the actual temperature of the engine coolant. On normal level roads mine usually reads around 208-210. The more strain you put on the engine (going up hill, towing, etc, the warmer the engine is going to run.

As stated, the Pentastar V-6 runs much warmer than previous generation engines. There is also a red warning symbol to her left and a little above the center line of the temperature gauge. It looks like a thermometer with heat lines coming off of it. As long as this light does not come on, your engine is ok.

You may want to take a garden hose then the engine (and radiator) is cool and squirt water from inside the engine compartment through the radiator and see if there is any blockage. Any blockage of the air passages in the radiator will cause warmer coolant temperature.
 
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the hill is about 20 min going up in about an average of angle 30 degree
No, it's not. I little simple math will tell you that, if we assume you are driving 60mph, you would climb 10 miles in your 20 mile drive up a 30* slope. That means you climbed Kilimanjaro twice, then climbed one of Colorado's 14ers.

As far as your temp gauge advancing while climbing what is likely a 7* slope, welcome to JK ownership. Too much rig, not enough motor. You can spend a bunch of time and money trying to fix the problem - and I have - but in the end you'll either swap in an LS or learn to turn the heater on when going up long climbs. The position of the needle in your photo translates to 235-238*, IIRC, but you can easily verify that in the EVIC. I don't bother setting my TD2 alarm to go off 'till 240*, as that's when I back off, if I can, or flip the heater on.

Mark
 

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No, it's not. I little simple math will tell you that, if we assume you are driving 60mph, you would climb 10 miles in your 20 mile drive up a 30* slope. That means you climbed Kilimanjaro twice, then climbed one of Colorado's 14ers.

As far as your temp gauge advancing while climbing what is likely a 7* slope, welcome to JK ownership. Too much rig, not enough motor. You can spend a bunch of time and money trying to fix the problem - and I have - but in the end you'll either swap in an LS or learn to turn the heater on when going up long climbs. The position of the needle in your photo translates to 235-238*, IIRC, but you can easily verify that in the EVIC. I don't bother setting my TD2 alarm to go off 'till 240*, as that's when I back off, if I can, or flip the heater on.

Mark
Oh jeez, that explains it, on top of climb the air density has dropped to about 10% of that on sea level. There's just not enough air going through the radiator to have sufficient cooling effect 🙃
 

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On a more serious note: people in general are very, very bad at estimating inclines. I'm guessing, based on my own experince, that the aforementioned 30° is in fact at most about 10°.

There is quite a steep hill nearby, it feels like about 30°, I've pedalled down it at about 45mph... well, anyway, just checked, and it's actually about 8° 😂
 
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