Knocking / bearing sound from top end Help please

[dannyberlingo]

Hey my dad has a 1.6 hdi and the other day it just started making a noise from the top end almost sounds like its from the cam shaft bearing the noise sounds like a catching bearing noise like a small thud. yesterday i stripped down the side of the engine changed the timing belt and waterpump as it needed doing and some one said that it could be the water pump. so i rebuilt it and the noise is still there just wondering if anyone knows if there is a common problem with these cars?
thanks im a little bit lost as to what i should do next

[taxi]

Sure you will get all the help and advice here, best of luck.