I have a 1996 2.8 3L hilux(jap import) and a knock/rattle noise appeared from the head area,I thought at first pre-combustion/swirl chambers were slack in the head but after removing the head everything was perfect as it should be, including the swirl chambers.There is nothing untoward at all from my inspections, the noise appears about 2000-2500 rpm when the engine heats up, it is not always apparent and is not rhythmic like a big end knock, it sounds like something loose near the top rear of the head.The only thing im not sure about is the EGR valve assy, could this unit rattle as it wears? The engine has 230Km on the clock.There are heavy sticky oil deposits in all the inlet tracks and ports, could this be significant as this is the first diesel ive had to tear down.
Any ideas especially on the EGR system would be appreciated.

You re-opened a thread that's been dead for three and a half years for that?

And it is his first post!