Originally Posted by RichieST

No need to drain coolant or remove alternator....

Follow top radiator hose to the thermostat housing where you will see 3 of 4 torx screws holding the thermostat cover on. Undo these, pop out the thermostat and put the new one in. Re-fit the cover, job jobbed. You'll loose about a litre of coolant so refill the level as required.