I recently purchased a 2007 Subaru Forester 2.5 non turbo and i see its leaking oil pretty quickly. About every 2 or 3 weeks i need about half a quart or so. I see on the driver side its kind of wet with oil around the dip stick area which i assume is a valve cover issue. However on the passenger side its leaking onto the exhaust right about the oil filter. I see where it looks like its leaking from and its right at whatever gasket is right about the oil filter. I personally can't tell if its a head gasket or a valve cover gasket and ive heard mixed things from people. The car never over heats and has no white smoke and everything seems perfectly fine except for the leaking oil. Is there any way to tell for sure if its head gasket or not?