Hi there, anytime your getting a loud intermittent clatter from the top of the engine you have to be concerned of the possibility of a timing chain issue
a loose guide or weak tensioner can cause a clattering against the chain.
now if you listen with a stethoscope and find that the noise is NOT behind the top of the front cover and actually coming from the valve cover area then you would need to inspect further and possibly remove the cover and inspect.
if you still need help though let me know please.
Thanks for that. We haven't had a recurrence yet, but if it comes back I will try to listen to it and find out exactly where it comes from. Is this a regular problem with that engine?
I certainly would not call it a regular problem on this engine.
but it does happen occasionally and the symptoms are usually pretty consistent
let me know if you need anything else.