Chain Rattle
 

Get chain rattle on start up in the mornings and have just noticed if I rev the car, as the revs are dropping it also has what sounds like chain rattle......tensioners??

forgot to add that the noise is coming from the rear of the engine..

Many people, including myself, get a very brief rattle on start up, but if you are getting it once the car is warmed up, I would rule out something more serious. I would at least take out the oil filter to check for metal. If you have any significant amount, then I would pull the sump plate and see whats in there. Also, check the cam deviation with the Durametric for early signs of IMSB failure.

I wouldn't drive it until I checked it out.

When one of the catalysts starts to go bad, pieces break off of the internal honeycomb structure and their bouncing around in the housing can sound like a pretty serious rattle. This is happening to many of the Boxster secondary cats that are now beyond the 7 or 8 year warranty. They are very expensive to replace, like $1,800 apiece. It would be great if one of the aftermarket folks jumped in to make these, but at present its a Porsche-only replacement part.

If anyone has any more positive info on this, please post it.