The classic N54 weeper. The OFHG had been leaving spots on the driveway for a while and there is no fixing it without pulling the housing, so three days of swearing, knuckles, and a torque wrench got the gasket replaced, the oil cooler back together, and the cooling system bled. New oil and filter while everything was already apart, fresh coolant for the same reason. The driveway is dry. We will see for how long.