Are you sure that the oil pan gasket is leaking? There have been many mistaken cases that was really just oil spilled from changing the oil filter. Sometimes the oil will run along the seam of the oil pan flange as well as the slightly higher crank support girdle. The spilled oil will run across the front of the engine before dropping down near the front crank seal and the back edge of the pan. I have had several that only needed to have the spilled oil carefully washed off.
