Drain coolant via the red drain plug on the radiator.
Remove plenum - see other guides on this site
Remove inlet (6 bolts, one air feed, 2 fuel pipes and one injector loom) to reveal sandwich plate and thermostat:
Remove black sandwich plate (12bolts), and pop some kitchen roll in the inlets to stop anything dropping down onto the inlet valves.
Undo its bracket, and move pas reservoir out of the way to give more access
Undo 2 bolts holding thermostat housing to engine block.
Remove B(arstard)-Bolt. In this picture of a 3.2, its the red one, not the blue one, most cars won't have the blue one, as dipstick is often held on with the B-Bolt...
Rotate the transfer pipe in relation to the thermostat housing to seperate.
Clean up the mating surface on the engine block with a bit of wet and dry
Replace seals on transfer pipe (if not replacing transfer pipe), and apply a smear of grease or vaseline to them.
Pull back the transfer pipe to allow room for thermostat to attach to engine block, and torque it to 20Nm, then push transfer pipe into thermostat
On this 3.2, the B-bolt only holds tarnsfer pipe and engine lift bracket. Others, the B-bolt goes through transfer pipe, dipstick, engine lift bracket.
Thats the stat done
Refit PAS bottle.
Refit sandwich plate, tightening the 12 bolts to 20Nm
Refit Inlet, remembering to plug in injector connector, tightening 6 bolts to 20Nm
Refit Plenum
Refill 50:50 coolant and bleed