What he is saying is temps while towing are higher than the set points of all the thermostats so it shouldn't make any difference which one you are running because any one of them would be fully open anyway. Seems logical but I see jhl3's point as well, the ability to cool down for the next grade.

 

Long stem = OEM style pump

Short stem = IH style pump

They are not interchangeable, or so I have been told by reputable sources.

 

I don't deserve any reps for this one guys. All I did was copy & paste some reference material. Thanks anyways.......


What baffles me is the difference in operating temps some experience with different thermostats. The only think I can think of is the difference in stem sizes or possibly different passage sizes. I don't get it......

 

Yes, that was the point I failed at making. But even on the "cool down" for the next grade the EOT is still not dropping below 210, so both thermostats will still be fully open......I don't get it. But if it's working for him thats all that really matters. I just can't figure out why in my head

 

I get that is what's being said, but I am here with firsthand experience to say it does not work that way. There is a reason I pulled over into a rest area in the middle of a long pull up a 6 percenter to change my 203 back to a 180. My oil temps were sky high for what they should be. The 180 made the difference. There are a few others on here that tow heavy and went the same route with the same result. If the temps always ran at a certain temp no matter when towing or not, then what would be the point of a lower temp thermostat? My 180 does not allow my temps to go higher when towing. that was the whole point of changing back over. Anyways, semantics I guess...

 

I am getting ready to tow 5K on mountain grades in 2 weeks, I did swap my 203 out and put my 195 back in but now you have me thinking should I swap in a 180?

 

nothing beats first hand experience. Glad it worked for you. Was the 203° thermostat a short stem or longstem?

 

I shall measure the openings in a few months.

There is one additional thing that is missing: What does the second spring and disk on the bottom of the long stem thermostat do exactly?

On the 180*F t-stat, there is almost no tension on the disk when compared to the 193* and the 203*.


On my rig it does in fact drop below 210* on occasion. Also, when I am not towing heavy it will stay below 210* on all but the hottest days and in addition to that, if there is nothing in the bed or behind me, temps will be right around 190-200* with the 180*F depending upon speed. Something is different. Joey has never explained what the difference is even when being severely ridiculed on the other forum. By virtue of that fact, some may believe that there is no difference. My experience says otherwise.

Again, there is nothing visibly different to my middle aged eyes. I'll have to use a set of calipers to measure the openings and, due to your valuable input, the stem/shaft. Having stated that, I still would like to know what the lower, smaller spring controls...unfortunately, my mind never gives a break...

_

 

When the thermostat is closed there has to be some way for a little bit of water to circulate. On my old Cummins 400 in my heavy truck it was a little poppet kind of thing on the edge of the thermostat. What does this engine use? Is it possible that that weak spring lets the T-stat open a smidgen to let water through when it is otherwise closed?

 

The 180* has what I would call a small "bb" sized "ball/float valve" on the side to allow a bit of flow and to assist in the purging of air.

The difference in spring "compressivity" is huge on the long stem.

 

Well, since water boils at 212°F. I guess a guy could throw them in a pot of water and see what happens

 

203 Long Stem from Dieselsite. I have never used a short stem. I have removed a few, but would not use one. Imagine changing a thermostat on a REALLY hot engine under duress of towing a grade....not fun...LOL

 

I don't know how you did it! I would've pulled over to the nearest ice house and grab six beers and waited till the morning

 

Probably what I should have done ahahahaha