Pentastar V-6 cooling questions

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engineering

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Supercharged?! Pictures or it didn't happen...
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Hevel

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I will say, I installed the NAPA thermostat last week. It said 190, but it most definitely sits at 200. On the stock, running on the interstate I would sit at 187-190, but have massive temperature fluctuations at say a red light. Sometimes jumping to 220+.
 

Keifus

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Hi Erik,
yeah the mysteries on what parameters are used and how the systems integrate is a bit frustrating. I have not gone "hog wild" on researching and experimenting but I think I can help with a couple of your questions.
AGS = "active grill shutters". There are shutters in front of your radiator ( behind the grill ) that open and close to control air flow into the A/C confessor / transmission cooler and radiator. It is a fuel mileage thing. What parameters are used to open and close them seems to be uncertain. I would imagine that thee is some temperature set point but do not know what that is. Some say they open whenever the A/C is turned on. I have also read that they possibly open when tow/haul is engaged. If you delete these entirely you will get a check engine light because of the mechanism on the activating motor that senses the position of the shutters. There are devices to defeat this however, the easiest and most cost effective way is to leave the top shutters installed and leave the bottom shutters installed. They are installed in pairs, left and right. This keeps the stop on the motor mechanism functioning as designed. Tons of you tube stuff on this. It is easily done ( take your time removing the grill ) and is quite effective at lowering both coolant Temps and engine oil temps. I did this and have near identical results to what 15 handicap achieved.
Engine oil cooling is a fluid to fluid heat exchanger that is part of your oil filter assembly. You cannot see it as it sits below the intake. Because oil is cooled by engine coolant as an engineer I am sure you can see the correlation between engine coolant Temp. and engine oil Temp. Very often my oil temp and coolant temp are identical. Usually my oil temp will be about 6-8 degrees cooler than engine coolant temp.
The transmission as far as I know does not have an additional cooler installed on vehicles with a "tow package". The transmission oil cooler is a fluid to air heat exchange that occurs in a portion of the A/C condenser. I believe the transmission oil cooling takes place in the top portion. In other words that device that sits in front of your radiator is compartmentalized ( is that a word? LOL ) to perform two functions.
There is a ying / yang situation with the transmission temperature control. There is a heater, ( yes you read that correctly ) on the side of the transmission. A transmission Temp. control unit . Like the oil cooler this heater is a fluid to fluid heat exchanger. Hot engine coolant is run through one side of the device and heat is exchanged to transmission fluid. This facilitates faster warm up of transmission fluid as well as maintenance of a predetermined Transmission fluid temp as dictated by a thermostat in this " Transmission Temp. control unit". No matter what you do with coolant thermostats or Active grill shutter delete the transmission temp will not be effectively made cooler. The thermostat in the transmission Temp. control unit functions independently in such a way as it will divert tranmission fluid away from the cooling circuit and direct it to the heating circuit until the set Temp. is achieved and maintained. There are a couple of ways to defeat this and there are more than one thread on the forum where it is discussed.
In regards to the engine coolant fan, seems like I run across comments from the Hemi owners in regards to switching their fan system over to the electric Pentastar system. Must be a reason for that.
Hope this helps with some of your questions.

Edit: Just noticed that you have a 2014 year RAM. I honestly do not know how much if any of the information above applies to your model year. My RAM is a 2017
Here are some detailed specs for the pennstar v6
 
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Different Drummer

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I will say, I installed the NAPA thermostat last week. It said 190, but it most definitely sits at 200. On the stock, running on the interstate I would sit at 187-190, but have massive temperature fluctuations at say a red light. Sometimes jumping to 220+.
So it runs about 10 degrees over what it is rated at but remains steady now? Looks like you made some progress. The 10 degree discrepancy might very well be in the gauge and associated sensors accuracy.
With the center sections of My AGS removed and OEM thermostat mine runs steady at 197 on the open highway, so pretty close to your 200.
 

Hevel

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So it runs about 10 degrees over what it is rated at but remains steady now? Looks like you made some progress. The 10 degree discrepancy might very well be in the gauge and associated sensors accuracy.
With the center sections of My AGS removed and OEM thermostat mine runs steady at 197 on the open highway, so pretty close to your 200.
Definitely progress. How much fluctuation does yours have under normal use?
 
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Different Drummer

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Definitely progress. How much fluctuation does yours have under normal use?
Literally 90% of my driving is long distance. In city driving and in mountainous regions in summer months I have seen it at 210 degrees since modifying the AGS. Also this is the only time my engine oil Temp. may exceed the Engine coolant Temp. Otherwise my oil temp is always 6-10 degrees less than my coolant Temp.
On the highway there is very little to no fluctuation. City driving will see some fluctuation but no real wild swings. I am not sure whether or not the electric fan ever activates now.
I don't think it does which makes me think it is programed to come on at a rather high Temp.
 
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Keifus

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Dose any of y’all’s start @ 100 degrees the first time you start it even when it’s cold outside? Could that be what’s throwing everyone off? Just a thought.
 

Boxman

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I'm a little late to this discussion, but fwiw. I have a 2013 3.6 pentastar 4x4 club cab with 105k Temps. It has active shutters.
The temp runs 215 to 220 all the time. During S Calif hot summers when going up slower mountain roads it reaches 230-232. The oil hits 235+. Had the plastic thermostat housing crack @ 100k miles. With new housing and thermostat, still get same temps.
When truck was new, I took in to dealer because of these Temps. They checked it out and said "all OK, they just run hot."
 
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