common fault with hdi RHY[DW10TD] type engine,
rubber inside pulley collects road grit and oils breaks bonding on metal surfaces in side pulleys, if left to long they fly apart
and can damage cam belt /water pump /anything that get in its way
replace as soon as possible ,
had 9 now over 13 yrs on my old pug 306 glx hdi
got changing them down fine art,
len
January 2014