ive got a diesel ford mondeo 2ltr, with like 65k on clock. the diesel knock is so loud now, i think its gunna blow up or something, its really pissin me off. i think its so loud, cos the oil that was put in by this dodgy garage was too thin, im thinkin if i change it to really thick oil, it might shut up a lil bit? or might it be somethin else? anyone kno?