3.6 Pentastar coolant temp 222 degrees at idle

[ATL_Rubi]

Can people please post their coolant temps at idle? I first noticed this yesterday while waiting in traffic. As mentioned, ambient air temps were in the 40s when I first saw it hit 220. I pulled off to a parking lot to monitor the situation, then shut the Jeep down. I restarted and it did it again.

Being the weekend, I decided to drive home just in case something was wrong. When I got home I let it idle and watched it go up to 222 on the display, then fall back to 213, then rise, then fall back. I suspect this is "normal" for this engine, but want to verify. Once it stops raining this morning, I will check the coolant level and make sure it is ok.

Is there a scan tool out there that will allow me to monitor thermostat and fan operation from inside the cab?

Mine will do this if I’m driving normal, then hit a parking lot/drive through, and start idling. It’ll climb to 210+ no matter the temp then drop back down

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[BlackRuby23]

This screen shot is after pulling a 200lb trailer 75 miles on flat land / 55 mph max speed; and idling for about 10 minutes.

Very strange. Why is my Jeep running so much hotter when it's not even working hard?

 

[FloridaMan655321]

I need to double check, but I feel like mine is the same temp at idle as it is while driving. I have the max tow, so maybe that is why?

 

[sharpsicle]

Just remember folks, colder isn't always better. Not that I'm saying north of 220 at idle is a good thing, but the apparent quest to make temps run as cool as possible doesn't always make sense. There does come a point where you've gone too far the other way.

 

[BlackRuby23]

Just remember folks, colder isn't always better. Not that I'm saying north of 220 at idle is a good thing, but the apparent quest to make temps run as cool as possible doesn't always make sense. There does come a point where you've gone too far the other way.

My original post is about whether or not my brand new Jeep is operating as designed or if there is a problem. I'd like to keep it at that.

 

[Pismo61]

My original post is about whether or not my brand new Jeep is operating as designed or if there is a problem. I'd like to keep it at that.

My JK ran like yours.My JL 2.0t is about the same.Moving on the road they both come down to 195-210 depending on weather,going uphill,down hill etc.Just watch it and see if it stays the same.If it does all is good.

 

[Mr._Bill]

My original post is about whether or not my brand new Jeep is operating as designed or if there is a problem. I'd like to keep it at that.

It is operating as designed. There is regular debate about the design, but it is within the limits Jeep deems acceptable.

 

[BlackRuby23]

I took her out for another drive and just got back. Temps are under 200 on the highways and biways. I pulled over and looked out over the water for about 5 or so minutes, letting the Jeep idle in park. The coolant and oil temps both steadily climbed from 195 to 208 or so. I figured they'd probably climb back to the 222 and didn't see any point in continuing so I shut her off.

I drove back home and temps were again normal in the sub 200 range. The road leading to my driveway is gravel with a 15 mph speed limit, and my driveway has a steep entrance. When I stop and park the engine is 206. I guess what is going on is that these engines like to creep up in temp at slow speeds and when idling. I think the stop/start feature will be employed when necessary to prevent this creep.

 

[Hootbro]

You are going to fret yourself over something there really seems to be no concrete answer to what is a exact "normal" idle coolant temp.

Dealership is not going to entertain anything to troubleshoot if the vehicle is reporting it within it's own "normal" operation range and using random other peoples temps as a reference point is not going to move the needle for them.

Of all three of my Gladiators, "normal" coolant temp at idle varied from 215 to 221. Nothing I ever put them through caused them to over temp and the cooling fan system kept things under control.

Attached is what I have on the cooling system description and operation and also a troubleshooting guide. It really lacks data on temperature ranges other than saying the thermostat starts to open at 190 and is fully open at 212.

IMHO, I think yours is running as it should. Only remote issue may be some air still trapped that should eventual burp out or possibly you have a temperature sensor (located on thermostat housing) that is on the higher end of it's resistive range. None of that is worth chasing your tail over though.

 

[bucolic]

My original post is about whether or not my brand new Jeep is operating as designed or if there is a problem. I'd like to keep it at that.

Everything is fine with your Jeep. Here is another thread that beat this to death on the Wrangler forums and another thread from this forum. The consensus is this is normal so you have your answer confirmed by many Jeep owners. You don't have an issue.

https://www.jeepgladiatorforum.com/forum/threads/normal-coolant-temp-range.22334/

https://www.jlwranglerforums.com/forum/threads/average-coolant-temp.114962/#:~:text=Different driving and weather conditions,probably nothing to worry about.

 

[ShadowsPapa]

Everything is fine with your Jeep. Here is another thread that beat this to death on the Wrangler forums and another thread from this forum. The consensus is this is normal so you have your answer confirmed by many Jeep owners. You don't have an issue.

https://www.jeepgladiatorforum.com/forum/threads/normal-coolant-temp-range.22334/

https://www.jlwranglerforums.com/forum/threads/average-coolant-temp.114962/#:~:text=Different driving and weather conditions,probably nothing to worry about.

Finally some sense and no fear-mongering and solutions looking for a problem.
220 area is 100% normal. In fact, it's good for the oil. That's a FACT.

222 at idle is fine, it's not broken.
Thermostats start to open at the rated temperature - and aren't fully opened until at least 20-30 degrees later, depending on the thermostat, etc. - so that means the factory is not concerned about temps in the 220 area otherwise that stat would be wide open at 195-200. It's not.

In short, the answer to the original question is - it's fine, nothing is broken, ignore it. As long as it cools down while moving and doesn't climb up to the 230 area, it's just fine and doesn't need a thing.

I've got charts as well.........for normal.

 

[BlackRuby23]

Thermostats start to open at the rated temperature - and aren't fully opened until at least 20-30 degrees later

From everything I've found, including the literature in the PDF files above, the thermostat is fully opened by 212 degrees. Something tells me that's not enough at idle, and the cooling fan doesn't come on until 221 or 222, so that's what's happening. I found this cooling fan info after reading the above literature:

During the fan activation, speed selection and deactivation of the radiator fan is based on the value of engine thermal variables that the PCM continuously monitors through direct equipped sensors, estimated algorithms, or it could be through request via Controller Area Network-Chassis (CAN-C) Controller Area
Network-Electronic Powertrain (CAN-EPT)

CAN-C Inputs
• Electronic Climate Control (ECC)/Heating, Ventilation, & Air Conditioning (HVAC) request
• A/C refrigerant pressure sensor information
• Engine oil temperature
• Engine coolant temperature
• Engine RPM
• Engine run status
• Intake air temp
• Engine thermal management demand
• Vehicle speed
• Commanded ignition switch status
• Hood ajar status
• Ambient temp sensor voltage
• Maximum A/C demand to powertrain
• Transmission fluid temperature
CAN-C Outputs
• Radiator fan PWM duty cycle command [%]
CAN-EPT Inputs
• Air flow request
4
CAN-EPT Outputs
• Radiator fan request
Hardwire Outputs
• PWM command signal to the radiator cooling fan

 

[willys 41]

Here is the way the radiator fan works
The fan comes on at about 15 to 20% fan speed at 221 degrees and only come on at about 75% at 231 fan speed
This is why you are seeing high coolant and oil temps
The RPM extreme fan controller will have your fan come on at a lower temp


When the engine is running the PWM fan will run at a low Idle speed (15%).
When the module reads the engine temp it will command the fan to the desired %.

Fahrenheit

199 degrees = 30%
205 degrees = 50%
212 degrees= 75%
218+ degrees = 100%

My average coolant temps after the fan controller are 190 / 195 degrees and pulling a long hard hill temps maxed out at 212
Jon at RPM extreme has been making these for years for the JK and about 6 month ago making them for the 3.6 JL

http://www.rpmextreme.com/Product/311/Jeep-JL-PWM-FAN-CONTROLLER.aspx

 

[willys 41]

BlackRuby23
You are correct
My thermostat starts to open at about 188 degrees and is fully opened at about 212

 

[ShadowsPapa]

From everything I've found, including the literature in the PDF files above, the thermostat is fully opened by 212 degrees.

Yeah, that fits if it's a 190 stat - 190 + 22 is 212
So the 20-30 fits.

It varies with thermostat/engine and so on.

I was giving historical numbers and generalizations, showing that a thermostat does not just open at the rated temperature, it only begins to open then and is not fully open until a number of degrees higher.

A 190 stat doesn't mean a 190 degree operating temperature, it is the minimum operating temperature. It will remain closed until it hits that temperature.
We used to put stats in a pan of water and gradually increase the temperature of the water until the stat just began to open, then check the water temperature in order to determine if one was good or bad.

The fan comes on at about 15 to 20% fan speed at 221 degrees and only come on at about 75% at 231 fan speed
This is why you are seeing high coolant and oil temps

He's seeing totally normal, not high.
You seem to be the only one who thinks that normal gas engine operating temperatures for the last several decades are high.

A solution looking for a problem............

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