Hello, I recently got a 1987 325i sedan and believed it had a blown head gasket. After replacing the head gasket I'm still getting COOLANT in the OIL. I believe the head or block or maybe both are cracked. My questions are, what are the differences between the pre/post 9/1987 engines? What is compatible with the pre-update block? Can I use the updated head and pistons on the older engine? Does the updated engine swap right in? I guess I need to know everything about this "update" as I cannot find pre-update engines.. My car is 03/1987 according to Mdecoder. Thanks, -D.