Hey every1 noticed recently my disco has started to become really loud, it's fine on tick over and when revved freely but when I'm driving its sound like a tractor like a knocking noise, can hear it when accelerating but can hear it even louder when travelling at constant speed say just cruising at 40, I've done a search an read alsorts of different things just wondered if any1 could pinpoint a common problem or had Similar experience, I don't want to carry on driving It If it's causing even more damage, oh also it quietness down after about half an hours worth of driving but not by much, cheers