Just pulled this from Ford workshop manual.
[i]Thermostat
The 1.6L Duratec-16V Ti-VCT engine is equipped with an electronic thermostat. The electronic thermostat will manually open if the coolant temperature has reached 98°C and there is no current flowing to the thermostat electrical element. When the engine is under load the electrical thermostat will receive a current from the PCM. The electrical current will heat the element inside the thermostat to allow the engine coolant to flow through the radiator when the coolant temperature has reached 60°C.
Assuming it applies to versions used by MMC, it goes some way to explaining unexpected coolant temps especially with non-standard installations.
This technique was also used on the early 1.8 and 2.0L Duratec engines. Fortunately it was dropped on the later builds used in our Morgans and replaced with a standard lower temp opening stat. Because the thermostats is located remotely at the bottom of the engine on the cooler coolant input the mechanical stat might not react quick enough to sudden temp increases from hard acceleration etc. So the ECU can detect the sudden head temp increases and activate a heating element in the stat housing to encourage it to open if necessary . I think they call it progress…….
