2009 1.6 auto estate rattle

Hi Guys, have had the car for three years, mileage is 35000 always serviced, the car  has in the last couple of weeks developed a rattle type of noise from drive belt side of the engine, the noise is apparent when the engine is hot or cold, and can still be heard at motorway speeds  the car seems to be running fine , warranty has now run out, so any advice would be welcomed