Very easy to do.
Remove 3 bolts from front of housing and the front will come right off, and the t-stat is right there.
Buy a haynes manul and it will give a good detailed description with pics.
Zetecs run hot and the temp gauge isn't very accurate,
as long as your not in the red above normal you're alright.
Change to a cooler (180 degree t-stat), change coolant, and add water wetter to coolant, and you'll be nice and cool.
