Unless it's a motrcraft thermostat I'd just go ahead and order the motorcraft tstat the part # is rt-1195.

 

That part number is for a 195 degree thermostat which is stock on these engines.

 

It would make sense for the 1195 to be a 195° I hate to tell you but your wrong though rt-1195 is a 54mm 185° I still have the box and the old oem 185° that I took out of my v10 the new thermostat is in my truck Rt-1234 is 192° 54mm there is no actual 195° stamped motorcraft tstat atleast that I found and if there is it's part number isn't rt-1195 no matter how much sense it would make the stant tstats are indeed stamped 195° though I've also gotten a brand new motorcraft tstat in a brand new stant box for the 195° part # that I didn't buy for a v10 which is not unheard for that to happen it was stamped 192° . As far as I can tell rt-1195 replaced rt-1177 as the 185° tstat. Since your username is fordmerc I don't know if that means your ford tech but if you are that should make it pretty easy to get ahold of an rt-1195 and take a peek.

 

You're correct, it is a 190 degree thermostat. I just received some bad information.

 

It's a 99 but serviced 4 times before this. Complete flush. Green should carry me until I sell it...if I sell it.


https://www.ford-trucks.com/forums/1...ue-solved.html

 

as I see it ford calls it a 190° since that's were the engine temp should be in the 188°-193° range under normal conditions with a properly functioning cooling system.
After looking at your other thread I hope you used distilled water this time.