Hi mate

There isn't a 'howto' for this yet in the
Maintenance Section but it is dead easy to do on a 4 pot. You can fit a new thermostat on its own, you do not need to replace the whole housing.
The thermostat housing is on the right hand side of the engine (looking from the front of the car) just below the silver cam cover. There is a large diameter hose going to it from the top right of the radiator. It is held on by 2 torx bolts ( I believe T11 IIRC). Partially drain the coolant into a dish via the radiator drain tap (red round handle on right bottom of rad, accessible from under the front of the car) with the expansion tank cap off. Undo the large hoseclip & pull off the hose from the thermostat housing & tuck it out of your way. Now remove the small hose below it ditto. undo the two bolts & remove the housing. If the silicone 'o' type seal is intact, you can reuse it with the addition of a thin bead of 'instant gasket'. The thermostat is removed from the housing by pushing down on it and twisting to free the fixing lugs. The new thermostat is fitted by doing this in reverse
If the sealing ring has been damaged on removal, then you can just refit the housing using 'instant gasket', but let it 'cure' for a few minutes before refitting. Refit the hoses, top up your coolant with the stuff you saved & it's done!
Note: I do not know the VX part no. but the one I bought was numbered
600KHere are a few pictures of the stat housing & Seal. When you buy the new stat, make sure this shape seal is included.


