ECT question
Stinky is a fire breathing dragon in the cab - I have to turn the heat down to 1/2 temp and fan to low to remain comfortable in the winter.
Here's something no one has mentioned: Have you checked your fan clutch to make sure its not failed in an "always on" manner? A fan clutch can fail either on or off, just like a t-stat. Having the fan engaged all the time will definitely drag down your oil and coolant temps. Unless under heavy loads, these 7.3L's just don't seem to need much help from the fan. Even in 90deg heat in the summer, mine would rarely come on, unless I was sitting in heavy traffic for a while.
It should be fairly easy to hear the turbofan like woosh if your fan is engaged all the time.
While a oem Ford t-stat should work ok, personally I have the DieselSite 203* one installed. 203* is the OEM INTERNATIONAL specified temp. ( Ya know, the people who engineered/designed the motor) Diesels run cleaner and more efficiently with a little more heat. I have had mine in for over 2 years with no problems.
http://www.dieselsite.com/dieselsite203thermostat.aspx
http://www.dieselsite.com/pdffiles/h...nginetemps.pdf
Here's a brief quote from the website:
Diesels run most efficiently at approximately 200° or above. A factory equipped 192°/195° thermostat will maintain an operating temperature at approximately 165°-170°. The Powerstroke has such an efficient cooling system, that this low flow when the thermostat is slightly open is normally enough to keep the engine cool. The downfall to this is that the engine -- when our trucks are not under load -- never begins to reach its optimal operating temperature. Our 203° thermostat maintains a minimum operating temperature of 190°. This brings the operating temps up from as low as 170° to as high as 203° depending on the operating conditions of the truck. This is closer to the operating temperature range that is preferable in our trucks for optimal efficiency.
When our trucks are under load and are producing higher combustion temperatures the 203° will allow the engine to run even closer to its optimal operating temperature. If the truck is under load and reaches the 203° setting, the thermostat is then fully open. This means you are at the maximum coolant temperature that the truck will reach. Your maximum temperatures are only a few degrees higher than in stock configuration, but these are degrees that you want for better performance. The best benefits come when the same truck is under a light load and would have a hard time reaching this optimal temperature. As stated above, you will never reach this optimum temperature with the stock 195° thermostat. The end result of installing the 203° thermostat should be slightly better fuel economy, less smoke, and maybe a few extra "ponies" to go along with it.
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Here's what I'm seeing exactly on the scan gauge 2. ECT warms to 254 and then instantly drops to 127(I assume this is when the t-stat opens) since the gauge in the dash isn't even reading yet and the oil temp is around the 120ish range I find it hard to believe the coolant is actually 254 other than maybe right where ever the pcm is pulling its reading from.
After this truck continues to warm and EBPV runs until truck hits 144 on the scangauge 2 then it no longer engages unless ECT drops below 144. Typical temp I'm seeing is 155-165 which is the same as the old t-stat would do. Reason I don't think the new t-stat is bad.
Another note. about as high as it got is about 165 temp wise this summer even with ambient temps up in the 70's and 80's. Only time I would see the 190's was pulling our fifth wheel or horse trailer.
Fuel mileage isn't suffering I'm seeing 16 consistent and sometimes 17 hand calculated
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Here's what I'm seeing exactly on the scan gauge 2. ECT warms to 254 and then instantly drops to 127(I assume this is when the t-stat opens) since the gauge in the dash isn't even reading yet and the oil temp is around the 120ish range I find it hard to believe the coolant is actually 254 other than maybe right where ever the pcm is pulling its reading from.
After this truck continues to warm and EBPV runs until truck hits 144 on the scangauge 2 then it no longer engages unless ECT drops below 144. Typical temp I'm seeing is 155-165 which is the same as the old t-stat would do. Reason I don't think the new t-stat is bad. ......
Also, are you sure your monitoring the correct PID on the scan gauge? There are some wacky ones that just don't work right. I can't help you with that though. Maybe Tugly,or someone else familiar with Scan gauge configuration, can help there.
There is no way your coolant is 254*. It would be at a rolling boil and puking out of the overflow/degas bottle. There is also no way, coolant temp would instantly drop 127* ( in half) from the t-stat opening.
There is no way your coolant is 254*. It would be at a rolling boil and puking out of the overflow/degas bottle. There is also no way, coolant temp would instantly drop 127* ( in half) from the t-stat opening.

I don't know about you, but I would certainly be able to tell if the fan clutch on my truck was stock on. It is like a Harrier jet trying to land vertically under the hood when the fan is on. Even at 55 MPH or so it is very clear the fan has kicked on.

I don't know about you, but I would certainly be able to tell if the fan clutch on my truck was stock on. It is like a Harrier jet trying to land vertically under the hood when the fan is on. Even at 55 MPH or so it is very clear the fan has kicked on.
I also wondered about the pid which is why I checked it with the thermometer to find the temp was about the same. Plus it corresponds with the EOT once the temp drops to the 127. I find it hard to believe it hits 254 also. The first time I seen it do it I about crapped.
1. It is not the fan stuck on.
2. It is not the thermostat stuck open.
3. It is not the sensor.
Not much more involved really...
. Second off, I too see the same temps running if not loaded. I just switched tstat from a duralast to OEM 195*..now, highest is 180* no load, 195*ish towing, do see 210*ish up hills.... with high 17mpg. Even hit a 18.19mpg last month..Duralast stat, gauge never above 160ish, unless towing...i always chaulked up my low temps to the coolant filter....run your truck, because mines been this way fur 7yrs 👍












