ALFAPAT

Have a similar noise myself,(2.4jtd.) before this happened the the main aux pulley went, the rubber disintegrated so it was changed along with te diesal pump which blew the seals unrelated I know but was producing a hell of a diesal knock.
Since then the aux belt has been removed and replaced because the gear box has been dropped yet againfor the clutch issue I am having, so I think an extra strain has been put on the aux belt drive chain, as in belt, because its dismantled to allow the engine to tilt.
The aux belt and tensioner pulleys were replaced last year with genuine alfa parts , so surely this is not at fault?
I suspect either the alternator bearing or the aircon bearing to be next , but not fully investigated yet

PAT