grinding noise from front

[stevie2505]

hi i just got a 1.4 9n 52 plate polo, driving in low revs was fine but if you get the revs up theres a grinding noise at around 5k revs and it goes away if you go past it. any advise welcome thanks stevie.

[guv.c]

mine used to make a grinding noise... until I changed the water pump.

[spud43]

is it a rotating noise?
Alt bearings or one way pully, a/c compressor, old aux drivebelt, aux drivebelt tensioner, or anything in timing belt area like slack belt etc