Not exactly having good luck here, finally figured out my coolant leak. How often does this happen to n54's? I know blowing head gaskets arent too common but an external leak at the head has me surprised. The car was compression checked and cyl 1 was 18% down and the rest were fine, but no misfires and the car still runs great (at 127k). No oil in the coolant, and I changed the oil last week and no coolant in the oil either. Just curious if it's happened to anyone else. I have an entire spare low milage motor ready to go in so I'm not really sweating this. It consumes about a gallon of coolant every 600 miles currently, and consumes zero oil over a 3000 mile oil change intervals.