civic ctdi 54 plate pinking? (urgent)
 

i'm about to purchase this car on sat it has only done 4500 miles,when i
test drove this car a few days ago i noticed under light acceleration i
could hear a slight mettallic ratting sound (quite faint) i've told the
sales guy and he said everything will be checked over before delivery and
assures me everything will be ok,the reason i'm cautious cause i had a fiat
bravo that had a very similar problem except the fiat sounded a bit
louder,anyone heard of these new civic diesels pinking? and what else to
look for?