I'm going to replace my thermostat housing and thermostat because its leaking . I heard the hotter the better for mpgs and such. But someone told me the hotter the less hp. I got a new 203 to put Into it already .... True or false

 

203 is what you want .. Among other things , the hotter the engine runs , the better it burns off crank case condensation ...

 

If your pulling heavy Rick, then which one do you recomend?

 

I'd run the cooler one in your situation glenn.

Cause your gonna run warm anyways.

Make sense?

Though I don't think 2 or 3 degrees is going to make a huge difference no matter what.

 

http://www.google.com/url?sa=t&rct=j...55272958,d.aWM

203° IS THE TEMPERATURE THAT NAVISTAR DESIGNED YOUR TRUCK TO RUN AT. THIS IS THE THERMOSTAT THAT WAS AND STILL SHOULD BE IN EVERY POWERSTROKE 7.3L.

Until 1996, all 7.3L Powerstrokes that were manufactured used an International water pump and an International short stem 203° thermostat . In 1996, Ford changed to a lower degree 195° thermostat. They changed water pump designs at this time as well. The new pumps required the new long stem 195° thermostat in place of the short stem to properly seat the bypass disk. All 1996-2003 Ford PSD's now come equipped with a long stem 195° thermostat. Recently the factory replacement thermostat available at the parts counter changed to 192°. Our Dieselsite 203° uses the correctly sized t-stat with the correct temperature spring so that we no longer have to give up the benefits of running our vehicles where they were meant to run.

 

When the t-stat is open all the way it is flowing the most it can. If your towing temps are at 210* and up then a 192* or a 203* t-stat does not matter.

Where it matters is when your not towing. The higher 203* t-stat allows the coolant temp to stay closer to the optimal temp (203* like Navistar designed) and your towing temps.

 

I have run all 3 stats and saw no difference in mpg with any.
IMO it's a good idea to run the 203° becasue that's what IH wanted.
However, when I pulled my fans off last spring, I also dropped in the 180 stat I had. Figured it'd help keep temps down when I tow.
That 20° also keeps the oil temps down quite a bit, too.
With the 203° the oil was well over 220° in both of my trucks, now it's 200°. I think I'd rather keep my oil temps low and just not worry about the possible increase in running efficiency, which I never saw real benefits of anyway.

 

Technicalities with tuning and oil tempature but its possible to make more ponies with tuning and a colder T-stat because of the hydraulic pressure differences with the oil at 190 vs 210.

If your running duals, its recommended you run a cooler t-stat to counter the effects of the hpop overheating the oil as well.

 

any chance the lower temp thermostat was part of Ford/Navistar/IH's plan to reduce cylinder wall cavitation issues.

being that cavitation is local boiling of coolant, my thinking has always been that they attacked the problem in at least 3 different ways:

1. a chemical solution - add SCAs to the coolant to coat cylinder walls with a sacrificial layer and locally prevent the cavitation
2. a pressure-based solution - pressurize the whole coolant system to effectively raise the boiling point of the coolant (from high school chemistry - as pressure goes up, so does the boiling point of liquid, in this case water/ethylene glycol)
3. a temperature-based solution - change the temperature at which the thermostat opens so that the coolant circulating past the cylinder walls is maintained at a lower temperature.

i'd be curious to know if anyone disagrees with my thinking. i don't have access to secret Ford/Navistar files, so i can only guess at how these are all related...

 

Alright good feedback. I'm gonna try out the 203. See if its better worse or same. Let you guys know. I haul scrap metal sometimes. But not too heavy. The heaviest I think was 4500 lbs + 2000 pound trailer

 

I really think you have to see where EOT is a given situation. There are allot of factors that tie in. Not just the thermostat.

Condition of your cooling system, average ambient temperature in your area, condition of your drivetrain, running a dual HPOP setup, what motor oil you run, tuning, injectors etc all figure into the equation. What is your rig used for. You have to match your components to your goals and use of the vehicle.

 

Well put Pete! You have to do that 'overall analysis' when doing any big mods to your truck.
If you ask me.
If you are just looking for a toy to throw money at, then less thinking is required. lol

 

I'm going with a 180 from Joey. Like Pete said, how/what weather you use your truck? Mine is used for towing only, in warm/hot months. I like the cooler oil temps like Jim mentioned.

 

x^^^ I also decided to go with a 180*. Pulling that 5er last summer in the heat with a 203*, this summer I want with my new toy to stay cooler. I always get lousey mileage anyway, so who cares about efficiency.