Have you seen the cooling system on an IH trucks an IC? They are huge not like our "small" radiators and IC. Higher EGT will also cause your engine to run hotter as well.

 

I have been running the 205 thermostat from Diesel Site for 3 years now since purchasing the IH pump from them right after I bought my truck. I have towed 10K lbs or more from coast to coast and my truck has run great.

I get great MPG's (see my signature) and consider my truck to run very well.

I have never monitored the EOT while towing, or not while towing and know that the fan only kicked on when traveling through the deserts out west when towing heavy. I thought for a while that the fan was broken on it because it never really turned on, except when out west. Even now when towing through the mountains of TN, the fan does not kick on. Maybe the manual transmission has something to do with keeping heat down though as I do keep the truck in the power band. Keeping the truck in the power band also keeps the EGT's down too.

I have thought about going down to a lower temperature thermostat in the past for no real reason. Although, knowing that the thermostat for the IH pump is a short stem, it has been enough to sway me from doing this. Also, I had thought that what real difference could a 192 thermostat really make opposed to a 205 degree thermostat.

Although, Adam may have just put the straw on the camels back that broke it. I have had this thermostat in my wishlist on Amazon for quite some time, it might be about time to go ahead and get it.


I believe it was Nicmike who told me this thermostat would fit the IH pump. I will probably add it to my next Amazon purchase and then install it when I tear into the evaporator coil.

 

I can't tell you why, but I gotta wonder how the cooling setup on the International badged rigs using the 7.3L differs from the cooling setup on the F250/350 trucks.

I know with my dual Termy pumps, running a 180* thermo is almost a must because of the higher shearing the oil is subjected to, and the oil temps run hotter with duals too, so a lower temp thermo is a good thing for my truck.

My Ex used to run the 203* Dieselsite thermo, but I took it out and replaced it with a stock 195* unit after a couple years because the oil temps ran higher, loaded or unloaded.

Stewart

 

I was just agreeing with the assertion based upon my experience. I change thermostats seasonally from either the 203* or 193* in winter based upon whether I am going to be in New Hampshire or the Carolina's, respectively, during the winter, to a 180* in summer regardless of where I happen to drive.

If you follow the progression of the thought that, "Do not use the 203 if you tow and want cooler oil temps" then, the 203* t-stat closes at or around 203* which will prevent the full utilization of the total cooling capacity available within the complete cooling system whereas a 195* or a 180* t-stat will allow the system to continue to cool the coolant more because the 203* t-stat is no longer the limiting factor in the overall loop. This affects the oil coolers ability to cool engine oil.

Having stated the above I can add a bit of additional information. If one were to change from the 203* t-stat to the 180* t-stat with all other variables remaining the same, a 23* reduction in EOT should not be expected from my experience during the heat of the summer towing 16k at 2500-3000' ASL. I have only seen about a 12* reduction....which makes me very happy. I also think that the fact that I only see a 12* reduction gives a hint to the limit of the overall cooling capacity of the entire system. I could be wrong.

Is it necessary to change thermostats based upon seasons or monitor EOT like a hawk? Probably not. I'll leave that up to each and every one of you to decide.

HEAT=Friction. As heat increases, so does friction. How much difference does 23* make? There are too many variables to consider.

I have read that HEAT is the #1 killer of these engines.

Air density decreases commensurate to gains in altitude so a turbo has to work harder to compress the available air while it works on approximately the same exhaust gas pressure which raises EGT's because there is less compressed air flowing though the intake side of the engine.

I cannot advise you on the WHY's of IH's choice to use the 203* t-stat. Why do you wonder about them?

-

 

^^^^^He said it and said it well. All I will say is this. I monitor my EOTs due to injector cup life and all of the other components subjected to heat. Heat is good, but too much is a killer. Here is my data from a few years ago towing 10k in the summer:

203* Thermostat--
EOT got to 245* on a long pull, cruising on the flat was about 230*
Cooant temps were at the M or the A and would not come down

180* thermostat--
EOT got to 230* on pong pulls, 215* cruising
Coolant temps never got above the O

Read about oil temps in race cars. They watch those way more than coolant because the hot oil is what will kill. Oil is indicative of coolant efficiency. 15* is a pretty big difference. Cooler oil=longer engine/injector/cooler/cups life. Just my opinion. Why International did it, I have no idea. They also put a squashed DP on an engine that needs to breathe. It doesn't we keep the downpipes because International put it there.

 

here is a keyboard FYI: to get a degree symbol as in 203° you push alt key down and input 0176 on keyboard, release the alt key and ° pops up.

 

Thank you for the very useful information. Alt 248 works on some too. Folks who have a 10-key keypad on their computer keyboard will find it particularly useful. Those that don't, not so much.

So, why are you interested in the reasons that IH chose the 203* [sic] t-tstat?

FYI: this keyboard doesn't, unfortunately, because it does detract from accuracy.


_

 

Tried the alt-0176 trick, did not work for me.

So, it is safe to say that on our trucks the difference between a 205* and 180* thermostat is roughly 12-15* lower EOT when towing.

I linked a 192* short stem thermostat that fits the IH water pump, does anyone know of a 180* short stem thermostat that fits the IH water pump?

Inquiring minds want to know...

 

I don't know of one. From my understanding, the short stem on our trucks is a killer because the back of the heads do not get as cool. I could be wrong. Maybe someone will show up in correct me if I'm wrong.

 

And yeah, that keyboard trick didn't work... And it's more work anyways, but thanks for playing.

 

From my experience yes.


From what I understood a few years ago, Joey at Terminator can custon "build/cut or lengthen/use a different bi-metallic" on the spring on a thermostat so that it opens and closes at your desired temp so he may be able to custom build a short stem.

I think I remember him offering a 170* t-stat; however, I don't think there is enough cooling potential contained in the design of the system to utilize a 170* in the summer. I CAN tell you that you will freeze your butt off with a 180* in sub-zero temps and it would be worse with the 170*.

 

I don't ever, ever plan to get back into sub zero temperatures, but you never know. I will swap to the 192* that fits the IH pump soon and call it a day.

That will bring the coolant flow down to where Ford says, but a bit lower than what IH said with the supporting equipment as Adam mentioned.

Thanks for the input and contributing to the conversation. I think this thread will serve as a learning experience for years to come.

 

That is my understanding as well which is why I was chastised 15 years ago for pulling a thermostat out of the housing when the engine ran hot and continued to drive the truck without a t-stat for about 300 miles. So, if that information is incorrect, it has been institutionalized.

It was 3 a.m. on a Sunday morning on I-10 between San Antonio and El Paso. I thought I had "done good".

 

I probably missed this in this thread somewhere but what is the desired oil temperature range on the 7.3 towing and not towing.

 

Well, not sure how to take this information, but I know that those of us that have utilized the IH water pump instead of the Ford we are limited to the use of the short stem.

I am confused by this statement. If you were under the impression that the short stem thermostat did not allow for the back of the heads to get cool, why would anyone give you a hard time about removing the thermostat altogether? Perhaps I am wrong with my thinking, but I thought if you removed the thermostat there was constant flow of the coolant and that would continue to cool the EOT until the coolant reached the point where it was not cooling any further. This would seem to be the opposite of the short stem thermostat, unless I am wrong...