Everyone under the sun knows about the old ecotec and rear main seal leaks. I haven't heard anything about the sidi engines whether 3.0 or 3.6? Reason I ask is, I have a 2010 Berlina sportswagon with 104k. Oil a nice colour, excellent service history, is due for a service now. No abnormal oil usage either. But I've noticed that the front of the motor has caked on oil. Like it's sweating from somewhere. The look of it is reminiscent of my vy v6 and a rocker cover gasket leak. Even after a 600km drive, I couldn't smell oil, nor does it physically leak on the ground. It's at the bottom part, about level with the alternator across the front of the engine. What could that be? Are there common engine leaks on these motors?