Sounds like my cam chain tensioner is in need of replacement. I'm getting a fairly load metallic sound from above the tensioner/chain so I'm guessing the tensioner/chain guide is worn. I will take the rocker cover off and check but I'm fearing the worst. I'll probably do the work myself to save £££s.. anybody got any tips, things to look out for etc? If anybody has had it done at a garage what's the going rate? Cheers.