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Running High Coolant temp

nlv_gonzalez

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I have a 2021 Bighorn 5.7 Hemi, switched out my thermostat to a 180, my coolant temp haves be as up as 246 and my e fan sounds louder then normal, Any ideas why its running extra hot is it normal to run that hot
 

nlv_gonzalez

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both temp gauge show normal, it sometimes goes just passed a lil half way but then goes back to running at 230
 
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User_3336

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Curious, why did you switch the thermostat to a 180 in the first place?
 

Rick3478

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I have a 2021 Bighorn 5.7 Hemi, switched out my thermostat to a 180, my coolant temp haves be as up as 246 and my e fan sounds louder then normal, Any ideas why its running extra hot is it normal to run that hot

Two thoughts:

1) It is possible to put a thermostat in backwards.

2) If you change to a significantly cooler thermostat without also changing the fan temperature setpoints, you may be running with the thermostat wide open and the ECU trying to control temperature with only the fan, which will have a lot more lag and may cause wider temperature swings than the stock thermostat.
 

Darksteel165

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Two thoughts:

1) It is possible to put a thermostat in backwards.

2) If you change to a significantly cooler thermostat without also changing the fan temperature setpoints, you may be running with the thermostat wide open and the ECU trying to control temperature with only the fan, which will have a lot more lag and may cause wider temperature swings than the stock thermostat.
^^^^^^^^^^^^^ This
OEM is 203 degree tstat
 
U

User_3336

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2) If you change to a significantly cooler thermostat without also changing the fan temperature setpoints, you may be running with the thermostat wide open and the ECU trying to control temperature with only the fan, which will have a lot more lag and may cause wider temperature swings than the stock thermostat.

Well stated!
 

nlv_gonzalez

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Two thoughts:

1) It is possible to put a thermostat in backwards.

2) If you change to a significantly cooler thermostat without also changing the fan temperature setpoints, you may be running with the thermostat wide open and the ECU trying to control temperature with only the fan, which will have a lot more lag and may cause wider temperature swings than the stock thermostat.
Thank you! I’m assuming I can adjust the set points when I have a tune. Just waiting for my unlocked pcm to arrive and I’ll be able to make that adjustment
 

Rebond

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There's also the chance the T-stat is bad even being new.

Stant sold out years ago. They used to be the best, but not so much anymore. My 180 Stant temps varied greatly, so I purchased another from Rock Auto, a GATES 34253S 180 premium and it's worked very well.

You really should program the fans with a tuner to get the most out of it.
 

GMetal

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Did you vac all the air out? Maybe an air pocket? Could also be a bad T-stat. A cooler T-stat would not need new fan temp points. The ECM only does what its told to do. I believe the fan set points are variable and the fans ramp up as the temp increases. Do you still have active shutters? Are they closed?
 

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