Hey weve got a Captivia 2.2ltz 61 plate auto with around 98k Got a knocking noise from something on the auxiliary drive train, weve removed crank pulley thats ok, renewed belt and tensioner all pulleys are running true no play in bearings . Weve noticed tiny shards of aluminium fillings in the auxiliary drive belt cover but cant figure out from where . If the drive belt is taken off the noise isnt there .....any ideas welcome or advice ..... any ideas thanks.... Many thanks Weve had it to the garage and hes stumped too 🤦‍♀️😞