997 Engine Problem
 

Thanks in advance for any help you can give me. I am now driving a Porsche 997.1 from 2008. Or, at least, I was. Suddenly there was a huge amount of smoke and rough idling upon start up so I shut it off and it was taken to my local Porsche mechanic (certified and years of experience). Upon tear down there was oil in the third cylinder and a bent rod. There was also slight oil in the other cylinders but #3 was the worst. We assumed it was the air-oil separator. However, upon tearing open the AOS we found it looked perfectly normal inside and the diaphragm was intact! The engine was never overfilled with oil. It has been maintained according to the manual. No problems up to this point. No major work ever done. I have full records going back to the original sale, one owner. My question is this: what else could cause oil to get into the cylinders besides the AOS? Also, the cylinders were ovalized, out of round. Could this be a cause of oil leaking into the cylinder? Could it be something with the intake manifold? Anything else??? Again, thanks. I'm going to have to rebuild the engine but would like to know what caused it.

this is the wrong forum for that but i'm afraid your problem is very common, you will get more information on Rennlist 996/7 section . occurrences just about every day over there.
Your engine is toast.

likely cooling issues causing bore scoring and oil shooting up and hydolocking cylinders. Its just ugly.

Thank you for your reply. I'll do more research in that direction