6.4 Hemi Thermostat

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Croz

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Hello, new to the forum. Seems like there are a ton of good people on here with experience and interest in helping each other out which is what I like to see.

I bought a new 2018 CCSB last year with the 6.4 Hemi and was surprised to learn how hot they make these run... I believe the thermostat is 215'F. So my question is because the thermostat is incorporated into the water inlet housing, is there anyone out there who makes a cooler thermostat?

The 5.7 hemi and the 6.4 in the cars have a different design and guys have swapped out thermostats with no issues, for some reason the 6.4 in the Ram seems to be a different design.

I only use the truck in the summer to pull our trailer and I am not worried about heater performance in the winter. Just trying to keeps the temps down a bit on the engine and the trans. Thx for the help with this
 

dbrock34

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Glad you asked this. I had to have a new thermostat installed over the winter and I've just started noticing it in the 220 range now that the weather is warming up. I couldn't remember ever noticing the temps before I had it replaced.
 

Bigseff23

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Not sure it would make that much of a difference as the fan is still going to kick on at the higher temp
 

68PowerWagon

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There are a lot of newer vehicles out there now that run hotter... like 200-210. Doesn't seem like anything is 180-190 like it used to be. Wonder if this has something to do with the newer emissions.
 

bigdodge

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That's the norm for these engines. It's not hurting it. My thermostat is stuck open and won't go over 200. I can't get one because they r on national back order for months. We could just trade [emoji16]

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Croz

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it is all about emissions the hotter you can make the engine run the cleaner it is and the less the cat has to do to clean up the exhaust. I was just hoping to knock it down to 195 or so... I wonder because these engines run 20' hotter then the 5.7 if that is why we run a thicker oil to compensate?
 

bigdodge

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I'm sure there will be cooler options eventually but as of now there aren't unfortunately. That's a good assumption on the heavier weight oil as more work = more heat.

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crazy jerry

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i would leave well enough alone. this isnt 1980 any more. removing the thermo would make the heater inoperable, the engine would likely run like crap and probly throw a bunch of codes because its to cold. i see no advantage in the summer either. theres 2 fans, your not going to over heat.
 

crazykid1994

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Hello, new to the forum. Seems like there are a ton of good people on here with experience and interest in helping each other out which is what I like to see.

I bought a new 2018 CCSB last year with the 6.4 Hemi and was surprised to learn how hot they make these run... I believe the thermostat is 215'F. So my question is because the thermostat is incorporated into the water inlet housing, is there anyone out there who makes a cooler thermostat?

The 5.7 hemi and the 6.4 in the cars have a different design and guys have swapped out thermostats with no issues, for some reason the 6.4 in the Ram seems to be a different design.

I only use the truck in the summer to pull our trailer and I am not worried about heater performance in the winter. Just trying to keeps the temps down a bit on the engine and the trans. Thx for the help with this

Question. Do the 2500 trucks have AGS (active grill shutters). I have a 5.7 1500 and the truck used to run at 212 all the time no matter what. I bypassed the ags system and now my truck hardly went over 203. I did just swap for a 190 thermostat and now my truck runs at 192. Truck runs fine with the lower thermostat

i would leave well enough alone. this isnt 1980 any more. removing the thermo would make the heater inoperable, the engine would likely run like crap and probly throw a bunch of codes because its to cold. i see no advantage in the summer either. theres 2 fans, your not going to over heat.
I don’t think he wants to remove the thermostat. Just install something less hot. I believe that’s justifiable for towing. The vehicle should be able to run slightly cooler without problems. It all depends what the programmed temp is in the computer for vehicle warm up. If I remember correctly the 5.7 motor warmup temp is around 180° Not sure for the 6.4
 

crazy jerry

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far as i know, theres no optional thermos. sounds like the op is jumping the gun and hasnt even hooked up to anything yet. unless he planning to pull a house, i dont see what worry is all about. like i said theres 2 large fans
 

R.D.J.

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The thermostat in the truck 6.4 anyhow is PCM controlled. Wires to your thermostat? Yes sir!
 

R.D.J.

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No sir. There is a temp sensor, however the thermostat has an actuator that is part of the assembly, and PCM controlled. The future is now.
 

crazy jerry

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ive got one in the garage and it does appear to be electrically controlled which might explain the constant temp fluctuations . its not like a mechanical thermo that opens and stays open until the engine is shut off
 
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Croz

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the 2500 trucks have no AGS system, and a mechanical fan. I pulled our trailer last year and it did fine, no overheat conditions or anything like that. the 5.7 runs a 203 stat and the 6.7 cummins runs a 195 stat... and the 6.4 in a challenger runs 203...not sure why the engineers want the 6.4 to run that hot in a truck. I am new to the Ram world and most of my experience has been with GM and I have been a driveability/trans tech for over 12 years. I have had several 8.1L big blocks and when I switched from a 195 stat to a 185 stat I verified with a scanner that the computer was able to leave more timing in the engine because of the decrease in cylinder temp. This helped with towing and power. I have no idea how the Ram's are calibrated, just thought the same theory may apply. I am not worried about an overheat condition as the trucks have a great cooling system and I am well below my max tow rating. Just wanted to run the engine and trans a little cooler while I am towing... as for the aftermarket...I think because there are very few ram 6.4's out there it is not worth their while to make an aftermarket T stat. The engine has been out since 2014, if they were going to do it it would have already been done.
 

jake Brekkestran

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I've had two new thermostats in my 2014 Ram 2500. Took the first one apart to see what the wires are on the thermostat housing. It seems to be a pencil heater to regulate the thermo-stat better for heat. Computer controlled. The 6.4 loves heat for optimal performance. They only had the one temperature rating. I'm seeing problems with mine now that I changed it again the other day. Was good at first. Drove it some. And back to blowing cold air. Mostly out of the drivers vents. More heat out of the passenger side vents. Not sure if I need to burp the air out of it. Or if it will eventually come out of it. Took the heater core hoses off and hooked up a clear hose to totally by-pass the heater core and I could pee more water thru the hose. I'm confused to why this is, when you should have full flow thru it at all times. When the heater core is by-passed even. Not sure, but is there a perimeter set in the computer at start up to open the thermostat to flow or my water pump isn't doing its job. All my hoses when I changed the thermostat the other day were very hot to the touch. Which a mechanic told me to check. Have some of you guys out there having issues with cab heating.
 

crazy jerry

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when coolant is drained from the engine you should use a vacuum system to refill it. per the service manual. this ensures no air is trapped in there
 

bigdodge

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I just got a 90 degree funnel and filled the radiator until it started back filling into the reservoir. Then filled the hose and slipped it on the radiator. Never had a single issue

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three D

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I've had two new thermostats in my 2014 Ram 2500. Took the first one apart to see what the wires are on the thermostat housing. It seems to be a pencil heater to regulate the thermo-stat better for heat. Computer controlled. The 6.4 loves heat for optimal performance. They only had the one temperature rating. I'm seeing problems with mine now that I changed it again the other day. Was good at first. Drove it some. And back to blowing cold air. Mostly out of the drivers vents. More heat out of the passenger side vents. Not sure if I need to burp the air out of it. Or if it will eventually come out of it. Took the heater core hoses off and hooked up a clear hose to totally by-pass the heater core and I could pee more water thru the hose. I'm confused to why this is, when you should have full flow thru it at all times. When the heater core is by-passed even. Not sure, but is there a perimeter set in the computer at start up to open the thermostat to flow or my water pump isn't doing its job. All my hoses when I changed the thermostat the other day were very hot to the touch. Which a mechanic told me to check. Have some of you guys out there having issues with cab heating.

mine has the same problem the only thing I haven't tried is replace the water pump. i flushed the heater core some junk came out but nothing to bad .when I rev up the motor it flows through the heater core and makes heat. but soon as it idles it slowly cools down again
 

68PowerWagon

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mine has the same problem the only thing I haven't tried is replace the water pump. i flushed the heater core some junk came out but nothing to bad .when I rev up the motor it flows through the heater core and makes heat. but soon as it idles it slowly cools down again

I am having the same issues with my 2016 Ram 2500. I have read on here where some guys say that they flushed the system to fix it & others have said they had to have the blend doors replaced. Flushing the system is not too big of a job but to get to the blend doors you have to pull out most of the dash!
 
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