Engine Oil Leaking problems of the 2010 Cadillac DTS

Tl-the contact owns a 2010 Cadillac Dts. The contact stated that while driving at unknown speeds or when vehicle was parked oil was leaking from the undercarriage. Additionally, a quart of oil had to be added every 10 miles. There were no warning lights illuminated. The vehicle was taken to an independent mechanic where informed that the oil pan gasket needed to be replaced. The local dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was not notified. The failure mileage 167,389 . Ap.