Not long ago, I was talking to the BMW repair shop who recently did a PPI for me on an used car. During our conversation, they mentioned to me that most of the late model BMWs have a tendency to need gasket replacements (for repairing oil leaks) as they age. This did not surprise me since it is a stereotype that German cars leak oil. The first thought that came to mind is that BMWs (and other German makes) spec long oil change intervals (10-15k). Oil change intervals of that length usually means that any acids will remain in the oil for a long time. From some of the UOAs I've seen, TAN often exceeds TBN at the end of the drain. I wonder if the long length of time that the dirty, possibly acidic oil is in the crankcase contributes to early gasket failure. Or, if there may be other factors that link long oil change intervals with gasket failures. Anyone care to speculate? Just a random thought and would be curious to see what trends others have observed.