I recently bought a very stock 2001 Ex 7.3. It was running cool, so I changed the tstat. From the looks of it, the tstat hasn’t been replaced (ever?). It’s now running fine / heating up / EOT from OBD around 200-215.

The truck runs well, so just I’m getting through the maintenance baselining.

My question: what if any maintenance would a long term open tstat suggest I add to my list?

on my list so far is flush / replace all fluids and filters, including ELC, CPS, clean exhaust back pressure sensor/tube. What else?

also working on CAD designed new center console. To be 3D printed. Happy to share that design when done.