Diesel Coolant Temp

cold gas

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Does anybody know the physical location of the sensor? That might help explain the readings.
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Gorilla57

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Bone stock no towing. It was 80mph at about 3k rpm wouldn't go any faster.
I’m thinking the ECU was de-rating the motor due to the water temps. I’ve done the Payson drive more than once with my Ram 1500 ED and it would accelerate well past 80mph when I needed to pass people. Something isn’t right w yours, but a dealership tech isn’t ever gonna figure it out. Those guys are just parts swappers, not mechanics.
 

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This here is what gets me = has Anyone’s dash ‘gauge’ ever gone above 1/2-way?
Absolutely when pulling my boat up a long grade at 117 degrees outside.....
 
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Lookie here...Maybe the sensor is on the crown of the piston...lol. Such bullshit

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rickinAZ

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Lookie here...Maybe the sensor is on the crown of the piston...lol. Such bullshit
I must be dense today. I don’t follow you. ???
 

JoBuck

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Very good testing of temps at various locations. What was the time difference between the readings. Also I don’t quite understand your statement about piston crown readings...
 
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Plongson

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I'm sorry...I was being facetious, and that doesn't come across so well on the internet.

Piston crowns are one of the hottest places on an engine. I was poking fun at MOPAR engineers for sending temp readings from from unknown (to us) location to a coolant gauge that would get everyone riled up.

Those reading I took were from running all day in 100°f heat and pulling into the shop. They were taken immediately, one after the other, including the dash.

On this engine, they were on the hose at the thermostat housing and the other was the upper hose leading into the radiator. TRADITIONALLY...this is the general area where we are use to seeing our temp gauge readings originate from.

I have absolutely no idea where the digital gauge signal originates from, but as was mentioned previously in this thread, there are many places where engine temps are quite high...(the pun about MOPAR engineers monitoring piston crown...).

I have taken to carrying a very reliable spot radiometer (spot IR) and checking periodically. The more I monitor, the less I'm worried about the digital gauge readings.

If it is accurate, it is being taken somewhere that does not reflect coolant temps like we are use to seeing and is useless (to us) without a frame of reference.

I'm becoming much less concerned with what the digital gauge is reading out.
 

JoBuck

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That’s the conclusion that I was leaning to as well but would like to put the issue to rest once and for all and the only way to do that is gonna require a trip to the dealership and talk to the parts dept... not the service dept... so I can look into the cooling system parts and diagrams on their computer.
 

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I would like to see a schematic of the cooling system with sensor(s) locations and ranges. This would help understand the numbers. The manuals don't list actual numbers only say things like "Higher than normal". The radiator cap on my JLURD indicates 21 PSI. For every PSI exerted on the cooling system, the static boiling point of water (212 deg F) is raised by 3 deg F. 21 x 3 = 63 + 212= 275 deg F. A little higher with Anti freeze., a little lower above sea level.
Coolant Temperature is not the best indicator of the metal temperature that is being cooled. Coolant flow increases heat transfer. So what is the flow rate of the water pump?

With these numbers, I feel comfortable with the coolant temperatures reported here. I also think my coolant temperature sensor is accurate. My garage AC indicates 72 deg F, and coolant temperature is reading 73. These sensors are most likely RTDs, which are simple but accurate devices.
 

Sydwaiz

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Lookie here...Maybe the sensor is on the crown of the piston...lol. Such bullshit

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20200816_145501.jpg
Unless you stick a thermocouple directly into the coolant stream, that reading isn't going to tell you much. That plastic hose connector is going to insulate much of the heat especially since it is made using a glass or carbon filled polymer. The reflectivity of the object can also greatly affect your readings.
 
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Plongson

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I respect your opinion but in my years of doing thermography work, the material used here would have negligible impact of the readings observed. Additionally the emissivity was corrected to .92. There is also no observed reflectance in the target.

I suspect I'm not going to convince you of anything regardless of my findings...This is after all just the internet...and no one really ever wins. I'm the original poster of this thread and I'm just about done here...got nothing more to add...Thanks for watching.
 
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