hi all i have an astra 1.6 16v 75000 miles its been parked up for about a week just took it out for a run and its now got a major top end rattle im prity sure its from the camshaft. it used to have a slight cam noise when cold but ok once warmed now all the time. its due an oil change but should i get the cam done first? carnt realy aford to get it done but dont want to chuck money at it to. what will happen if i just leave the camshaft? i will check oil level tommorow not done it for a long time is replacing camshaft an easy job? any advice appreciated