Originally Posted by Robf
heard about that before charlie, do bmw do it?
Yep. Seems to be partly due to the type of driving and if you do lowish miles in stop start then you can get coke build up though the newer oil breather reduces it. The chunks of coke get drawn up into the inlet hit the swirl flaps which are on pathetic little pins and rivets and then they dislodge and get taken into the engine. Rest is self explanitory seems to nearly always result in an engine write off. Huge thread on BMW forum about it. There seems to be a newer version of the manifold with slightly upgraded flaps some people have removed the flaps as they are only there to swirl the air up as goes in. Seems that I is so common that replacement engines can be hard to come by. BMW have assisted with labour fees in some instances and it seems that they know there is an issue but aren't going down the recall route for obvious reasons.
Place I bought mine (indie dealer) had had it happen to a customer and they had to replace the engine under warranty. I decided for piece of mind to get a new manifold and oil breather on purchase. I'm doing about 30+k a year on Mways so that probably helps too.