I am posting this question to satisfy my own curiosity as much as to see if this issue is wide spread. I was going to specify Z-51's only, but thought it would be useful to have all owners reply. Please make sure if you respond to this thread that you have your mileage and whether your car is a base car or Z-51 listed somewhere in your response. Also, if you do see oil around your air filter check your oil level (on a warm engine) and report what that is using the upper and lower hash marks on the dip stick as a reference. Thanks.