the tappets are hydraulic on your engine and are self adjusting if they are making a noise one or more of them have become stuck, the first a cheapest method is to put some oil flush (wynns £6 from halfords) run it through and then change the engine oil, if this does'nt free them off then you will have to replace them, that involves removing the camshaft and while you have it stripped down that far you should also replace the cambelt
nigel
March 2008