Duratorq Destruction!

[Sad Ford]

I have an 02 mondeo tdci 130 and it has covered 88k. I have had to replace the usual bottom turbo pipe, numerous sensors, wiring looms and just lately a set of really expensive fuel injectors. 2 days after getting it back from the garage the engine has developed a serious rattle, metalic knocking (sounds like someone is striking the engine with a spanner loudly) from either just below the cam cover or inside the timing chain cover at the front of the engine.

I am sure that there is serious damage being done to the engine but here is the strange thing. It doesn't make a sound when it is stone cold or when it is hot! It just makes this metalic knocking when the engine is just slightly warm and only when the engine is idling, if you rev it up a little the knocking goes away.

Has anyone ever heard of this before, what can I do, bearing in mind I have just paid £1,400 for injectors, I am at my wits end!

Any advise on the possible cause would be appreciated, Thanks