How do you get the thermostat to open?

[heavyequipment]

I use an infrared thermometer for checking temps in different parts of the engine. They're not hard to find these days. This engine is the only one I've ever seen that circulates the coolant "backwards", i.e. the water comes out the top and returns through the thermostat at the bottom. I wonder why they did that... The system should bleed itself by letting air out of the top of the radiator into the top of the surge tank. You just have to fill it up and then recheck it after running several times.

Regards,
Chuck Yarter