In the thermostat housing...
(If you are standing in front of the car, it's just to the right of the engine. You might see it better if you remove the water pump pulley cover (the plastic cover that at the very front/top of the engine). If you remove that cover (three bolts, very easy job), you will see a fixed metal coolant pipe (painted black) running along the top of the front of the engine, follow that to the right, where there is a short rubber hose attached, and from that hose is the thermostat housing.)
Sounds like a stuck thermostat.
yes
is this a 3.1l v6 or 2.4l 4cyl?
No , there is a rubber ring that goes around the edge of the thermostat
Mondeo Duratec 2.5 v6 is a duratec 25 which is chain driven on both sides.
1.4.2.5.3.6.
The thermostat housing is located behind the alternator on the front of the engine just follow the hose from the top of your radiator and that will lead you to the thermostat.
I'm looking where the therma stat is location in a 1996 Chevy bratta at
locate the top hose on the radiator drive side follow it back to thermostat housing it's were the clamp is at on the end of the hose.
The thermostat is inside the housing, it is on the motor where your upper rad hose connects to, hope this helps
its under the plastic manifold cover with duratec v6 on it,
Your 1996 Mercury Villager minivan with the 3.0 L - SOHC V6 engine is designed to use The Ford Motorcraft RT 1170 thermostat ( 190 degrees F / 88 degrees C )