Feel the heater hoses & they R hot B4 the thermo opens...
Engine temp food 4 thought. .
Here's a little background on the Ford Powerstroke thermostat...
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 203o thermostat . In 1996, Ford changed to a lower degree 195o thermstostat. They changed water pump designs at this time as well. The new pumps required the new long stem 195o thermostat in place of the short stem to properly seat the bypass disk. All 1996-2003 Ford PSDs now come equipped with a long stem 195o thermostat. Recently the factory replacement thermostat available at the parts counter changed to 192o. 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.