Cheers for this will help alot100k/10yrs mate :) check for any coolant leaks from vacuum tank on the right hand side of the dpf at the front of the engine also remove the engine cover and check the inlet manifold seals are not leaking before buying also check for a swooshing sound around the cambelt area/auxillary belt area when engine is on idle. if it is making like a swooshing noise ask for the cambelt kit and water pump to be changed
Your a star that this thanks!the noise is caused by a build up of dust on the guide pully and makes the noise when the engine is idling but we just replace the lot at work as its easier :)