Thermostat stuck on open or broken Engine Coolant Temperature sensor. So far, it was not necessary to know if you had a 2.5 V6 or 2.0 I4. Do you have a I4 Zetec Engine or 2.5 Duractec engine? And yes. Changing the thermostat or ECT sensor can be done by an amateur.
Not getting to 4th could be the OD off button being depressed.
Thermostat.
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