Went for a drive today in my 1.3 mk2 runs impeccably however there is an aweful rattle from what appears to be the top end. My guess is something to do with valves/cam's etc but i'm not sure. It doesn't seem to have got any worse and i've done 50miles + now but its just abit concerning.
The engine is a low mileage (50,000+) so shouldn't be worn but just after an opinion of what it could be... Things to check etc. I know its impossible to diagnose a problem by discription just writing on here on the off chance someone might have experianced the same problem.

Its defintly top end sound and a very fast tapping as if the valves are loose but I thought these were hydraulic tappets,I'm new to this vw scene and am an amature in learning when it comes to these things

Cheers guys your help will be much aprietiated