Thermostat seems to be stuck open. on 2003 BMW 330xi

How difficult is it to replace with a new thermostat? I have some mechanical ability but haven't worked on this car other than changing the oil and filter myself.

Asked by for the 2003 BMW 330xi
all data says 1.5 hrs depending on your ability you might want to have it done by a pro. there is a bleeding procedure to extract all the air