Oil Pan Cleaning and Inspection

WARNING: This page is about a different car, the 2002 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.

Clean the oil pan mating surface.
Clean the oil pan. Remove all the sludge and the oil deposits.
Inspect the threads for the oil level sensor and the engine oil drain plug.
Inspect the oil pan for dents or distortion.
Repair or replace the oil pan as necessary.

Fig 1: Oil Pan, Oil Level Sensor And The Engine Oil Drain Plug
Courtesy of GENERAL MOTORS CORP.