That still does not explain it - think about it, it is feeding HOT air into the intake charge when it's open! If it is closed, then it does not feed hot air in. I ran with Bob Land headers that did not have the EGR connection and had no problems other than the check engine light. EGR is an emissions additon and not a blow up your engine thing.

I do agree with the PCV being clogged and blowing oil out through the rear seal.