2023 Hemi thermostat and fan settings

[Slorango]

Last year I tried a handful of different 160f thermostats and all of them failed except for my current Robertshaw which has worked flawlessly, and with much better cooling because it does not have a bypass block off plate. I’m sure there will be people sharing their opinion about thermostat temperatures, we can agree to disagree. One of the first things I noticed with all of the thermostats was that after a few minutes of driving the cluster and UConnect would both show a false temperature of 185f despite the actual temperature being lower. For some reason Dodge has these set up to show 185f even if the temperature is below 185f after only a few minutes of driving. Above 185f it reads the actual temperature.

Fast forward to the last week or so and I’ve finally had the time to play with the fan settings, and some genius at Dodge thought it would be a great idea to trigger the fan off of the false ECT, not the actual temperature. After many hours and tune after tune I finally realized that any fan setting below 185f ramps the fan up to high no matter how cool the engine gets. If you target 185f, after the engine comes down to 185f or cooler the fan will not go below around 50%, I was logging the PW and I can’t remember the exact percentage. Finally I settled on 86c (186.8f) since I read to leave the fan settings in celsius and the fan works as it should, and will even shut off if the engine gets to 185f or below.

My first question, does anyone know of a way to target a lower ECT without the fan running all the time with the factory ECM?

My second question, is there a proper way to tune for P0128 or am I stuck turning it off? It doesnt throw the code very often, but on cold days it throws it more.

[LilSick]

email me the file

1) yes

2) not with a 160 t stat and a 2023 truck

[John_Carter_2]

Instead of getting scammed, share the file here.

People will help you!

[Hemituna]

My first question, does anyone know of a way to target a lower ECT without the fan running all the time with the factory ECM?

My second question, is there a proper way to tune for P0128 or am I stuck turning it off? It doesnt throw the code very often, but on cold days it throws it more.


I came up with one solution many years ago for this 160 stat issue.
With a 180 stat the 186c fan setting is a good compromise.
But, I am also a fan of 160 stats and found Grand Cherokee SRT's and Trackhawks do this same thing.
So with 160's, I fit a "temp tricker". Basically it is an additional oem temp sensor run in parallel with the original sensor.
I just grind smooth the end of additional sensor, press on a battery terminal and coat in epoxy.
Then bolt it to cylinder head just near the original sensor and connect in parallel.
This makes the temp reading to PCM/BCM 15-20c higher than it really is.
You need to readjust fan settings to more like 95c as that is what dash and pcm will read at operating temp.
A laser gun will show that engine is actually at 75-80c.
Obviously ECT related comps (cold start fuel etc) will need to be recalibrated.
This will fix P0128 also.
No doubt some genius has a simpler way, but so far this is what i do.

[Slorango]

That’s pretty genius actually lol, thank you for sharing. So in your experience the false 185f thing is shared with other Mopars as well, and they trigger the fan off of the false temp? I still don’t understand why an engineer at Mopar thinks its a good idea.

[LilSick]

I just grind smooth the end of additional sensor, press on a battery terminal and coat in epoxy.
Then bolt it to cylinder head just near the original sensor and connect in parallel.

wait what

huh

this thread is worthless without pics

ethanol seems to like 180 more than 160 but i gotta see this

: )

[mike_ct]

in my ram, the only table that does ANYTHING is the Fan Control PMW table. seems to be recognized when I make changes there

[Slorango]

Same with mine, but I can’t command anything less than 186f without the fan running constantly.

[Hemituna]

That’s pretty genius actually lol, thank you for sharing. So in your experience the false 185f thing is shared with other Mopars as well, and they trigger the fan off of the false temp? I still don’t understand why an engineer at Mopar thinks its a good idea.

So far have only noticed it on the Jeep Srt's and Trackhawks when using a 160 or 170.

Seems to be in the BCM not PCM. Durangos would be same.

So now I usually just do a 180 and set PWM fan to 86C. Too easy.

160 is a bit of messing around but is worth a few hp.

[LilSick]

do you set both ambient temp rows to the same value?

[LilSick]

another question:

the factory puts a low number in the upper left corner of the pwm stock fan tune for the late model jeeps

see pic

what is your understanding of this logic?

anyone?

[Hemituna]

wait what

huh

this thread is worthless without pics

ethanol seems to like 180 more than 160 but i gotta see this

: )

[Hemituna]

do you set both ambient temp rows to the same value?

Yes

[Hemituna]

another question:

the factory puts a low number in the upper left corner of the pwm stock fan tune for the late model jeeps

see pic

what is your understanding of this logic?

anyone?

Not seen any like this (yet).

[LilSick]

that is some genius right there.

combo'd with a lil mad scientist maybe?

lol

thx for the pic

[Slorango]

Thanks for posting the pic.

[1320bee]

Last year I tried a handful of different 160f thermostats and all of them failed except for my current Robertshaw which has worked flawlessly, and with much better cooling because it does not have a bypass block off plate. I’m sure there will be people sharing their opinion about thermostat temperatures, we can agree to disagree. One of the first things I noticed with all of the thermostats was that after a few minutes of driving the cluster and UConnect would both show a false temperature of 185f despite the actual temperature being lower. For some reason Dodge has these set up to show 185f even if the temperature is below 185f after only a few minutes of driving. Above 185f it reads the actual temperature.

Fast forward to the last week or so and I’ve finally had the time to play with the fan settings, and some genius at Dodge thought it would be a great idea to trigger the fan off of the false ECT, not the actual temperature. After many hours and tune after tune I finally realized that any fan setting below 185f ramps the fan up to high no matter how cool the engine gets. If you target 185f, after the engine comes down to 185f or cooler the fan will not go below around 50%, I was logging the PW and I can’t remember the exact percentage. Finally I settled on 86c (186.8f) since I read to leave the fan settings in celsius and the fan works as it should, and will even shut off if the engine gets to 185f or below.

My first question, does anyone know of a way to target a lower ECT without the fan running all the time with the factory ECM?

My second question, is there a proper way to tune for P0128 or am I stuck turning it off? It doesnt throw the code very often, but on cold days it throws it more.

Be careful not to get scammed. Feel free to send me a DM.