What is recommended, 192-203??

 

Factory Motorcraft will do great.

 

Doesn't really matter as long as you are not exceeding the degradation point of your selected oil when considering EOT. If I am remembering correctly, that is ~250° for conventional and ~450° for synthetic. I could be wrong though as it has been a while since I looked up the specifications.

I run a 203° and have for 8 years towing heavy in strenuous situations and all has been well.

 

I put an oreilly motorad brand 192 stat in.
it wouldn’t seal with the new housing and gasket so I put a bit of rtv around it.
i can already notice a huge difference. My heater blows out warm air and the truck has way more horse and torque readily available..
But if you guys think I should go get a motor craft oem 203 stat I will but I love it already.
The truck has been running for 5 years on an open thermostat...

 

A billet housing from @Riffraff Performance would be a nice addition.

 

Previous owner used silicon on my engine. Found some in the head after removong the cups. My guess is it was blue silicon.

 

I would also vote for a Motorcraft thermostat and billet cover. DONT use RTV, it breaks loose and clogs your oil cooler.

https://www.riffraffdiesel.com/therm...ssembly-96-03/

https://www.riffraffdiesel.com/riffr...ostat-housing/

 

The main advantage of the Motorcraft version is that it has a much better built in sealing gasket that doesn't leak at all, and the billet aluminum housings are a must have also to keep the rust and crud away. As far as the temperate ratings I didn't much difference between stock and the 203. Far more important is that it's a quality part that works correctly so OEM is the best bet here.

 

If you want to get into the weeds (completely unnecessary) of the thermostat, see the link below.

Link: https://www.ford-trucks.com/forums/1...-opinions.html

 

Correct,stamped thermostat housing most likely has sealing issues due to the warping.