[Tatsfield]

I read in a forum post that for a job which should be seen as the changing of a consumable, changing the thermostat is not the simple job that it is on most other cars. It's a poor design decision because thermostats slowly degrade and we shouldn't have to wait until the cars performance falls to a low point before realising that the change needs to be done.

On a previous car the regime was to change the thermostat and the coolant temperature sensor every 3 or so years to ensure that the running temperature of the coolant around the block and the coolant temperature reported to the ECU to control the fuelling were accurate and that the engine ran at its most efficient. It used to be the loosening of three bolts, removing the thermostat chamber cover, taking out the old one, putting in a new one, replacing the cover and tightening the bolts. 20 minutes work for the DIY owner.