hi guys, wondering if you could shed some light on something.

ive got a 2.0 tdi 140 sport and i noticed about 3-4weeks ago a whirring/grinding noise from the engine area, its non exsistent with the clutch pressed down but you can hear it when the pedal is up and you can hear it as you accelarate from low revs, it is the worst in 3rd gear but goes at higher revs (or engine noise drowns it out). it seems to drive fine and still accelerates as it always has. just a bit puzzled really . thought its worth a go asking you guys to see if any one has had a similar problem

help/info is much appreciated, THANKS