Thermostat is located between the 'V' right at the front just behind the cambelt and pulleys, to get to it you need to remove the plenum and inlet manifold / injectors. If you try to remove the plenum but can't remove the inlet couplings to the plenum, you can remove them by inserting a small screwdriver and they will pop open and you need to refit them by closing on the small catch then squeezing shut with pliers.
You need to remove airbox pipe, plenum top, taking care to remember all the plug locations, pop open those rings as I said before, then a torx socket (E10) iirc on an extention bar to reach down between injectors (shine a torch in to see them) 5 torx bolts in there. unplug then remove injector / manifold assembly,you may need to disconnect fuel lines but not sure. then it needs to be tilted to get it past the heads, can be tricky but possible. then you have around 15 (I think) torx bolts holding down the lower inlet manifold (black plastic) the oil cooler cover and thermostat will then be visible underneath. take great care when undoing oil cooler unions as they have a habit of breaking and be sure if you are resealing oil cooler cover that you use the Vauxhall BLACK sealant as it is best. plus i think the socket size is about 24mm for the big nut at each end of the cooler and it may be tight!
Another handy tool to have is a magnet on a stick in case you drop anything down the holes, always an idea to block them up with rag. and a very good idea to get a set of seals for the lower inlet manifold as they may have flattend.
Chicks Fan, December 2008
