The first thing to do is to remove the right hand front wheel and under tray and right hand side engine bay cover, making sure the car is lifted in a safe manner and supported on axle stands.
Then you have to remove the plenum chamber this is only secured by two allen keys hidden down behind it and once these are removed you have to disconnect all the pipes and wires from it, including the chrome inlet tubes, and then the engine breather pipe has to be removed from the rocker cover as you can’t pull the plenum back with it in place; now the plenum will pull off, on some models you will have to disconnect the engine management unit
Once you have removed the plenum chamber you can then remove the rear coil packs, these are secured by four 10mm nuts. when refitting the plenum make sure that you don’t trap any of the wires to the coil packs and be sure that you are happy with the spark plugs and coil caps as they are difficult to get back to if there is a problem when the car starts up again.
It is probably best to remove the front cam cover next and then remove the front coil packs and get them out of the way by laying them over to the left of the engine bay.
Now both rocker covers have to come off, this entails loosening three of the chrome inlet tubes in order to get at the securing 6mm allen keys on the rear cylinder head and be careful with the dip stick securing bracket on the front head once this is off the engine needs to be turned over until the cam locking tools fit and these should now go on their respective camshafts.
Number one plug can now be removed and the DTI can be fitted in its place.
Now we have to remove the auxiliary belt and both its tensioner and idlerand it is also best to remove the lower crankshaft pulley at this point. Next remove the covers from the cam belt, the upper cover is secured by three fasteners and then it pulls vertically upwards to remove.
Remove the auxiliary drive pulley and then both the lower covers are accessible these are secured by three 5mm allen keys and these are a bit tricky to get to and will include much skinning of knuckles. The cam belt is now accessible and can be removed by loosening its tensioner.
Before refitting it is worth considering fitting a water pump especially on the 2.5 V6 as the plastic impeller cracks and causes problems with engine cooling. It is always necessary to replace the tensioner as they wear out and if they break they will destroy your engine. In order to refit the cam belt it is necessary to loosen all the cam drive pulleys as they need to rotate to get the correct tension on the belt, once they are loose, tension the belt and then do up the pulley securing bolts.
From here on it is only a case of reversing the above procedure.