Yes, I am still running it. Thanks! My truck likes it.

 

I changed to the 203* about 2 mths ago. I havent had any problems, but havent seen any improvements either. My mileage dropped about 1mpg with the 203 vs stock.

 

I haven't ever considered trying the 203 degree stat. I tow a pretty good size box up a pretty good size mountain on pretty hot days. Last thing I want is a thermostat that opens at a higher temp.

 

I've been running the 203 since 2002. Had one in my 97 1ton and one of the first mods I did to my 550. I tow a large 5th wheel(18K) and I've pulled most every hill you can find between the Chesapeake Bay and San Fransisco Bay, gulf of Alaska to gulf of Mexico. Never had a heat issue, oil or water. If you have high temp issues you have more things wrong than 8 degrees in a T/stat. I like it, I'll continue to run it.

Barney

 

Can the thermostat be easily switched out? I have a 195* thermostat, but I'd like to try the 203* to see if my truck likes it. It seems to be a truck by truck basis.

 

It is easily changed. Just drain the coolant down below the T-stat level to avoid a mess, remove the 3 bolts from the housing, and swap it out. Put the coolant back in and your done. You can leave the upper rad hose attached to the housing if you like. I changed my upper hose to one that goes around the belt instead of through it.

 

I am swapping to the wrap around radiator hose when I do my coolant change. I just want to try both tstats for fun.

 

Been running a 203* since 2006 with no problems.

 

Maybe with the 180 there is less chance that the t stat will close!? I do see what you are saying. I was under the impression that of I installed a cooler t stat I would be able to bring some of my other temps down. But yea anything above 195 with my old t stat the both of the stats would be wide open.
But keep in mind I'm reading oil temps not coolant temps. I did notice it takes a lil longer before my programs are turned on since Jody has it set to defuel till the engine oil temp is up to around 170-180. Not sure on the specifics.

 

What do you think the "normal EOT" is? I'm running the 203* and just yesterday with OAT at 98* DP tuner set to 80E my water temp was 210* and EOT was 220*.

 

For me, that means anywhere from coolant temp to 10-15* above depending on ambient temp. My average EOT is 210* at ~ 98*.

 

Is it?

I'm curious if anyone has actually determined it is.

I ask because based on Joey's testing, not even the stock 195* thermo is completely open at 195*.

An interesting thread from FDP if anyone is interested: A cooler Thermostat? - Ford Diesel Power Forums

Stewart

PS - Not "questioning" you specifically Rick, just wondering out loud regarding the 203*

 

Quote from Dieselsite's website regarding the 203* thermostat (I bolded some statements pertinent to this discussion):
WHY IS 203* BETTER THAN 195*?
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 203o 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 195o 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

My notes: Based on this information, unless you are running under a constant load, you are NOT fully opening your thermostat and it SHOULD NOT be the major contributing factor for excessive coolant or engine oil temperatures. Since the engine oil returns from the HPOP back to the reservoir and the temp reading is taken there, it would seem likely that the HPOP is contributing its fair share to heating up the oil. Under a load, the HPOP is working harder to maintain the oil pressure needed by the injectors for the demand. Keep in mind, there is hot oil returning to the pan from other sources, i.e. the cooling jets after the oil sprays on the pistons. When load increases, many factors come into play. Just my 2 cents worth.

 

I'm running the 203 T-stat. The only different I noticed is that the truck gets up to operating temp faster.

 

run'n 195*, and with the temps here, last few weeks, in the low/mid 100's, my temp gauge banging at 200, all day long. Grant it, when cold/morning, run'n around, it sees 170-180*. Towing the other day/night, same thing, 200-205*..one last bit, the other week, going up Cajon Pass, no trailer nor load in back of truck, around 6am, temp reached 210*, but i was doing 85mph also....? Think i'm in agreeance with gchavez.