Hey Mate, did you work out what the issue was? Mine is exactly the same, does it worse once the motor warms up! Drives me nuts.Mine clatters at 80kph and weirdly sometimes the clattering noise completely disappears on a cold day or at night time. Bought some liqui moly diesel purge additive going to try that. Diesel filter housing with the plunger button on the top is very soft, going to replace that.