To replace an oil pan gasket, drain the oil reservoir, remove the oil pan and gasket, clean it, attach the new gasket, and reattach the oil pan. The required supplies include the vehicle service manual, a new oil pan gasket, a wrench, solvent, rags and thread sealer.
Drain the oil from the car. Consult the service manual to locate the oil pan, as placement varies between vehicle models. Expose the oil pan, and loosen the bolts with a wrench. Remove the bolts, set them aside, and pull down the oil pan. If the pan seems stuck, tap it gently with a rubber mallet. If it remains stuck, consult the vehicle manual and check the pan for bolts hidden by other engine parts.
Remove and discard the old oil pan gasket. Clean the pan and bolts with solvent until no sticky oil residue remains. Wipe the pan dry, and lay the new gasket in place. Apply thread sealer to the bolts, lift the oil pan into position, and hand-tighten the bolts. Finish tightening them with the wrench.
Replace any vehicle components you removed to access the oil pan. Replenish the oil supply, run the vehicle, and then inspect the crankcase to verify that the oil pan no longer leaks.