Up here, it's frogs.

 

Very pleased with my 203 tstat and billet housing and coolant filter too.

 

Based on my 8+ years of towing a heavy 5er with an F350 ...and listening to the radiator fan go into its full lock-up mode before I reached the tops of most long hills ...it's clear to me that the 7.3L cooling system shouldn't be compromised by installing a thermostat that's hotter than the one specified by Ford!

Towing with my F350 on days when the temperatures were 90*F or hotter ...started out with seeing how far I could go before I had to turn off the A/C to avoid listening to the drone of the radiator fan in its full lock-up mode ...and sometimes before the day was done I even had to run the heater to avoid listening to the drone of the radiator fan!

There wasn't anything at all wrong with my cooling system ...and I did the A/C mod and the Genedad2 mod as well ...and as my under the hood temperature measurements confirmed ...even towing on the flat places a high enough "sustained" load on the engine so that the cooling system is stressed to the point where it activates the full lock-up mode of the radiator fan ...and this is an observed fact ...not a theory!

Ford designed the truck to meet a variety of tasks ...not to be a fulltime tow vehicle which was my application ...that's why I cited the lower coolant temperatures being run by Cat and Cummins ...which were designed to meet the demands of fulltime towing ..and they have thermostat opening temperatures that are even lower than for the stock 7.3L thermostat!

The paper I originally quoted from was researching the additional wear that's caused by running with higher coolant temperatures ...because that's one way to increase MPG ...but the research showed that wear increases dramatically with higher coolant temperatures ...and that to combat this wear new materials would be required for the rings and cylinder liners ...and this is also a fact based on measurements ...not a theory!

During a 7.3L engine's B90 lifetime each piston slides along its cylinder wall for 132,000 total miles! If during this time the pistons rub against a cylinder wall that's hotter versus one that cooler ...then the wear rate increases ...I gave a "dog and pony show" that explained this ...and since no one asked any questions I assumed that everyone understood those pictures!

I'm still researching the subject of "abrasive wear" ...and this type of wear also increases at higher temperatures ...and "abrasive wear" is somewhat like a "nuclear chain reaction" ...if even one abrasive particle gets in between two sliding surfaces that particle generates several more particles ...and those particles grind off some more particles etc ...and if you don't change your oil frequently enough your engine will get a lot of additional wear that might otherwise be avoided!

Now if this 203*F thermostat was a potential cure for some deadly disease ...then taking it would be worth the risk of incurring some side effects ...but that's not the case here because you're trading off perhaps a few tenths of a MPG increase when running around town empty ...for some "unknown amount" of additional engine wear ...especially when towing ...and if the radiator fan goes into its full lock-up mode a little sooner than necessary it wipes out weeks of around town MPG improvement when running empty!

If you want to maximize the probability that your 7.3L engine will complete its B90 expected 4 billion lifetime power stroke heart beats ...then you should only use a stock Ford thermostat period!

 

"A thermostat regulates MINIMUM operating temperatures. A Radiator regulates MAXIMUM operating temperatures."

that seams pretty clear cut to me, I don't understand how a 203* t stat will increase engine temp while towing. My truck showed no noticeable differences in EOT or ECT's while towing after I switched to the 203* 4 years ago.

The EOT and ECT did increase during my around town driving about 5 or 10 degrees which I was happy to see.

as for the fan coming on during a long grade, I prefer it . I grew up in a family of truckers....we always engaged the fan at the bottom of the hill and just let her whine all the way to the top.

The fan was put there for a reason, to have issue with the fan coming on and doing what it is supposed to is counterproductive to the argument that ford put a 195* t stat in so leave it alone.

Ford put the fan on the end of the water pump to cool the engine so don't worry about turning off the AC and running the heater, just let the cooling system work as ford designed it and stay comfortable.

 

I still hold with the statement that airflow affects overtemp more than T/stats. if your truck is running hot while towing or even just running around do this.

REMOVE the radiator and pressure wash the fins until no more dirt, weeds, bugs an stuff comes out. you will be amaized at how much S**t gets caught there.

just washing it out in the truck won't do it, it has to be removed.
I've been towing heavy on a regular basis for 5 yrs now, north-south , east-west hot and cold. my temp guage very seldom even moves outside of normal. yes the fan comes on, but its supposed too! never for long just enough to drop that little bit.

Barney

 

Barney, I couldn't agree more with what you just said.
This picture was taken during my recent engine replacement.
Folks this radiator is located behind the intercooler which is located behind the AC condenser.
All that crap got all the way through the first two.
You can see along the bottom of the radiator where the intercooler ended because of the line of silt that had built up on the radiator core.
And the MUD that ran out of everything was phenominal!
The hardest one to get clean was the AC condenser. It was full of hair, bugs, pine needles, etc and had to be brushed.
Last time I was out on vacation, and pulling hills, I had to for the first time, turn off the AC because the temperature gauge was climbing when pulling hills.
Never had to do that before, and this picture explains why.
Now, it's hard to even get the top hose to heat up unless I'm driving it.
Idleing, forget it, top hose stays cool.
And for the record, I am more comfortable running with the 192 degree stat.

 

Fair enough and I don't see how anyone could find fault with that. I believe it mostly boils (no pun intended) down to personal preference and trying to prove or disprove wear and longevity issues based on an 11* difference in the t-stat you like to run and the 203* I prefer is really splitting hairs. I suppose that is what the internet is for so " carry on"

 

My reason for posting on this thread was to give some information about engine wear that I just recently learned ...and to explain that information well enough so that everyone can understand the potential tradeoffs involved with installing a hotter thermostat! The following points are a summary of some things I posted several years ago on a similar thread ...and even though these points aren't new they're still important ones to consider!

#1 In a turbocharged diesel the thermal contact between the pistons and their cylinder walls isn't sufficient for dissipating the entire heat load that's absorbed by the pistons from the combustion process ...and that's why engine oil is squirted onto the under sides of the pistons to help cool them ...and installing a hotter thermostat increases the temperature of the cylinder walls which also increases the temperature of the pistons!

#2 As the exhaust gas flows through the exhaust ports in the cylinder head some of the exhaust gas heat is transferred to the coolant ...and installing a hotter thermostat increases the coolant temperature which also increases the temperature of the exhaust gas!

#3 As the intake air flows through the intake ports in the cylinder head some of the coolant heat is transferred to the intake air ...and installing a hotter thermostat increases the coolant temperature which also increases the temperature of the intake air!

#4 Hotter intake air is less dense ...and this decreases the air-fuel-ratio which increases the cylinder gas temperature ...and increasing the cylinder gas temperature increases the exhaust gas temperature which feeds-back to point #2 ...and increasing the cylinder gas temperature also increases the piston temperature which feeds-back to point #1!

 

The graph below assumes a "clean radiator" and it shows why a 192*F thermostat is the correct choice for towing applications ...and I think the correct choice period!

Both the blue (192*F stat) truck and the red (203*F stat) truck are identical stock 250 FWHP automatics and they both start at the bottom of a long grade with equal coolant temperatures of 150*F ...and at T=0.00 min they begin a long steady climb in 2nd gear at nearly full power which results in a constant 100-hp heat rejection to the coolant.

During the first 1.00 minutes of the climb the performance of the respective coolant systems doesn't depend on either the "thermostats" or the "radiators" ...but only on the "heat capacities" of the coolants in the blocks which is the same for both trucks ...so both coolant temperatures increase at the same rate!

At T=1.00 min the 192*F stat starts to open ...and this begins to add the remaining 3 gallons of coolant in the radiator and the overflow tank to the total heat capacity of its cooling system ...and this means the coolant temperature in the blue truck starts to increase at a slower rate while the coolant temperature in the red truck continues to increase at the same rate as before!

At T=1.25 min the 192*F stat is fully open ...and a maximum flow of coolant is going to its radiator ...but the radiator can't quite dissipate the entire 100-hp of heat rejection to the coolant ...so the coolant temperature in the blue truck continues to creep up ...but at a lower rate than before the thermostat was fully open!

At T=1.25 min the 203*F stat is just starting to open ...and at T=1.50 min the 203*F stat is fully open ...and a maximum flow of coolant is going to its radiator ...but the radiator can't quite dissipate the entire 100-hp of heat rejection to the coolant ...so the coolant temperature in the red truck continues to creep up at the same lower steady rate as in the blue truck!



At T=3.00 min the waste heat build up from the radiator in the hotter red truck has increased its engine compartment temperature to 205*F ...and this activates the radiator fan lock-up clutch ...and this pulls more airflow through the radiator which allows the coolant temperature to begin a slow steady decrease.

At T=5.00 min both trucks once again have equal coolant temperatures of 210*F ...but the climb is over at this point and the radiator fan lock-up clutch didn't need to activate on the blue truck ...and during the last 2 minutes of the climb when the red truck's radiator fan lock-up clutch was activated and absorbing an additional 30 hp from its flywheel the red truck had to slow down ...so the blue truck beat the red truck to the top of the grade ...and it used less fuel while winning the race!

 

I read your posts and articles with a great deal of interest as you obviously know your stuff. I would like to throw in my .02 for whatever it's worth.

From what I have gathered the cylinder runs about 12% hotter than coolant temp. I got that from a post stateing 176* coolant, 200* cylinder temp. I can only imagine the piston and top ring temps are somewhat higher. With a 203* stat I would guess the cylinder temp to be about 225*F. If International installed the 203 in other versions of this engine, I can't see a problem with us using it. The only other application I can see for the 444E is in business class or industrial PIT trucks, both or witch work harder than the average pickup truck. Over the last 10 years or so, gassers have been running 205* stats. In the 70's we ran 160-180*'s and engines lasted about 100k miles. Today with the 205* stats, 200k miles is not at all uncommon. Somewhere there seems to be a line in the sand. Much like water, 210* is ok but 212* it's going to boil. The TRR temps you talked about seem very high to me but somewhere in the 108* spread the line was crossed. I wonder just exactly where that line is. The study would have to be done in smaller increments to find the "boiling point" or range. I would also like to know what the actual TRR temps are in our engines.

You have a good point about reserve cooling capacity. The point about a radiator controlling maximun temps is true but over time coolers get clogged with bugs, dirt, and cotton reducing their ability get er done. Under heavey loads, road speed is also reduced meaning less air flow through the coolers.

As a student in this discussion, your study proves what we already know. Overheating is bad. I don't think however it has proven the 203 to be bad. Feel free to educate me further.

 

Gene

What do you expect it to do under those conditions.
Its going to run hotter! Not one time have you used
the word i overheated! All i see is panic! That is just
what ford hope for. (ac shut off, heat on ect)
The psd heui is controlled by FORD software/hardware.
The IH software/hardware has provisions/saftey's to
omitt driver abuse, ford does not have this.

Under your stated conditions it dont matter if you have a 195
or a 203 installed the end result is the same. The 203 will just
get you their a little sooner. Your base coolant temp is higher.
The answer is not in a T-stat at this point.
It would be more about the use of water injection!
For you its simple with a trailer that carries water!

Above is not a statement that if the fan locks you are abusing the motor.
Its doing its job. It just that you can extract the generated heat into pushing
the truck up the grade.

.02
Bill

 

Based on some of the comments to my latest "graphical analysis" ...it appears I haven't stated my conclusions regarding how I "really feel" about the "203* stat mod" forcibly enough to satisfy some members ...so I'll try again!

At T=2.5 minutes into the climb ...the truck using the 203*F stat hits 212*F ...and it then needs to run its radiator fan in full-lockup mode for the rest of the climb in order to avoid "overheating" ...and that causes "unnecessary" wear and tear on the fan clutch ...and running the engine at full load with coolant temperatures above 212*F also causes "unnecessary" increased wear on the engine ...and it also "unnecessarily" drains about 30 hp from the engine to run that fan ...which is hp and fuel that could've otherwise been used to climb the hill!

While it's true this particular analysis didn't show the engine with 203*F stat actually "overheating" and "blowing up" on this particular climb ...it did show that running its radiator fan in full-lockup mode just barely kept it from doing so ...and in my computer model ...if I dial up the ambient temperature from 90*F to a little over 100*F ...then the fan is required to keep the temperature of the 192*F stat truck in check ...and the temperature continues to climb in the 203*F stat truck ...even with it's fan on ...and the 203*F stat truck does "overheat" before the end of the climb ...and the 192*F stat truck doesn't overheat!

But I'd never post that version of the analysis ...because on this forum the "203*F stat mod" is evidently just as "ingrained" and "emotional" as the "6637 mod" is ...and I learned long ago that engineering analysis and reason will never trump "emotion" ...so this is my final post on this particular thread ...and in closing I'll use my "emotional side" to put into words how I really feel about the "203*F stat mod" by saying ...if anyone would care to buy some FL "swamp land" to go along with their "203*F stat mod" just let me know ...because I'm in FL now and I might be able to get you a deal!

 

I've never been so confused.

I thought a thermostat just had a cup that expanded as heat went up, and forced more fluid through the rad?

I'd assumed a 203* stat would keep the temp around 203*, while the 195* would keep it around 195*......

Are we saying the 203* stat keeps fluid out of the rad longer, thus warming up faster, but really runs the same temperature as the 195* stat?

 

I think the temp rating on the t-stat is the temp at which its fully open. So yeah, the 203 would warm your truck up faster because it opens later. Not sure what the opening temp is though. IIRC, the 195 starts opening around 170.

EDIT: Found this back at post 75

 

OK, I'm not confused anymore.

Thanks.

I guess I was never that far gone, but I was overthinking again. aAAAARRRGGGHHH!!!