S80 D5 Automatic - engine idling question
 

Hi
I am not the most mechanically minded person, so bear with me!! I have a 2002 S80 D5 Automatic. However, recently, I have noticed that when the engine is idling in neutral, there is a rattling sound coming from the fan belt area. My mechanic examined this and wasn't sure where exactly the noise was coming from. I only had a new fanbelt and tensioner pulley installed last year.

However, as soon as the slightest bit of acceleration is made, the noise goes away.

My question is this. Is it possible to alter the idling speed (marginally) of the engine, and if so, what steps need to be taken?

Any help with this matter would be greatly appreciated.

Ciaran, Dublin, Ireland