2025 Pentastar coolant temperature

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Lilbxl

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Just purchased a ‘25 with the Pentastar. I had a ‘22 with the Pentastar without the etorque. Coolant temps were always around 204*. This new truck is running 223* to 235* on the highway. Is this normal temperature?
 

BenchTest

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I would say no, that's a not a normal Pentastar temp. Especially at highway speeds. Are you towing something heavy and running in hot temperatures? If then, MAYBE it'd run that hot. I routinely run down the road at 75-80mph with mine and I hover between 197-200. On a 95 degree day I'll see 205. Rolling hills and mountains added to 90+ degrees, I'll still be around 203-205. Unless they made a major change to the 2025, no, that's not OK.
 
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Lilbxl

Lilbxl

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I would say no, that's a not a normal Pentastar temp. Especially at highway speeds. Are you towing something heavy and running in hot temperatures? If then, MAYBE it'd run that hot. I routinely run down the road at 75-80mph with mine and I hover between 197-200. On a 95 degree day I'll see 205. Rolling hills and mountains added to 90+ degrees, I'll still be around 203-205. Unless they made a major change to the 2025, no, that's not Ok.
It has ran in this temp range 3-4 times. I’m guessing the thermostat is not opening when this happens. I just bought the truck on Friday.
 

BenchTest

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It has ran in this temp range 3-4 times. I’m guessing the thermostat is not opening when this happens. I just bought the truck on Friday.
Is it new or new to you? Mileage? Checked antifreeze level? How's the temps when moving around town (stop/go)?
 
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Lilbxl

Lilbxl

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Is it new or new to you? Mileage? Checked antifreeze level? How's the temps when moving around town (stop/go)?
Brand new. Has not hit those temps today. Highest was 207* which is normal. I was running 60 on the highway and in town speeds. Stayed 197* to 207*. Maybe it was just a fluke.
 

Wild one

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Brand new. Has not hit those temps today. Highest was 207* which is normal. I was running 60 on the highway and in town speeds. Stayed 197* to 207*. Maybe it was just a fluke.
How hard is it to get to the thermostat housing on a 3.6,if it's easy to get at,the next time it gets that hot,try tapping the housing with a wrench or something,and see if it cools off.If it's a sticky thermostat sometimes giving the housing a few taps will kick it loose,just don't get carried and bohunk hit the housing,light taps is usually enough to free up a sticky thermostat,especially if you're using something heavier like a hammer
 

BenchTest

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Nah something is not right thats way to hot air in the system maybe? back to the dealer you go..
This was going to be my next mention...air in the system. It's pretty common on the Pentastar setups to need a good air burp. This could have been an overlook during assembly.
 

star_deceiver

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How hard is it to get to the thermostat housing on a 3.6,if it's easy to get at,the next time it gets that hot,try tapping the housing with a wrench or something,and see if it cools off.If it's a sticky thermostat sometimes giving the housing a few taps will kick it loose,just don't get carried and bohunk hit the housing,light taps is usually enough to free up a sticky thermostat,especially if you're using something heavier like a hammer
I can’t speak for the 2025 version, but mine is right here. I can almost stand between the belt and the rad fan. If I were him, I’d check the grille shutters. Those being stuck closed will skyrocket the temps.
IMG_4055.jpeg
IMG_4054.jpeg
 
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Lilbxl

Lilbxl

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New thermostat that also comes with new coolant temperature sensor and all is good.
Well, it was stable for a while, now it back to acting the same way. The cold/hot gauge stays steady and doesn’t move but the temperature numerical readout fluctuates from 216 to 235 at 75 on the interstate.
I’m trying to post a video but do not know how.
 

Yardbird

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Take it in and have them check for codes. Your shudders could be sticking closed.

Or, if you can, unplug the shudders when they are open, and try driving it.

235 is very hot.
 
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Lilbxl

Lilbxl

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I wonder if it is actually that hot? The numerical read back shows that but the cold/hot gauge is steady and no where near hot. It is at the small mark between 1/4 and half mark lines.
 

BenchTest

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I wonder if it is actually that hot? The numerical read back shows that but the cold/hot gauge is steady and no where near hot. It is at the small mark between 1/4 and half mark lines.
Have a thermal/temp gun? You could check temps at the inlet and discharge of the radiator. Something is definitely not right.
 
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Lilbxl

Lilbxl

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I had not driven my truck for 2 weeks, away at work. So, I added almost a gallon of coolant to get it back to the operating level. Apparently they did not add coolant after changing the thermostat. The shutters are open. When I first get in the truck, temp will get up to about 207* then drop immediately down to 198*. But then after a few minutes of driving, it just keeps working its way up to 230*. It goes between 216*and 230* and that is where it stays at highway speeds with the cruise on.
 
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Lilbxl

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Just shot the temps, the readout in the instrument cluster is 10*-12* higher than any temperature I found with the temp gun. Truck got up to 230* while idling but fans never kicked on and temperature started to go down. ‍♂️
 
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