An engine oil leak may develop from the rear of the engine. This is commonly caused by a failed oil pump drive o-ring seal. The leaking o-ring should be replaced to correct this concern.Google+
Car Problem Reports
Buick Century Oil Pump Drive O-ring May Leak Oil From Rear of Engine
Buick Century Problem
Engine Affected: 3.1L V6
Average Mileage: 143,000 mi (115,000 mi - 171,000 mi)
Visitor, 2002 Buick Century, 3.1L V6, 171,000 mi
Engine leaking quart of oil every 300 miles. Big O Auto repair said oil pump O-ring seal needed replaced. Cost estimated at $450.00 (mostly labor). Technician had seen this problem many times before on GM 3.1 engines.