Q: Do I need to buy an Entire Valve Cover, or Just Replace the Gasket? There is some caked up oil around the Valve Cover.

Typically, valve covers are re-usable as long as the covers are not bent, dented, distorted, cracked, or otherwise leaky. The best practice is to thoroughly clean the cover so that you can carefully inspect it. BEFORE removing the cover, try to clean it (vacuum works well with brush) of as much loose dirt, especially grit, from the sealing area as possible so that the dirt does not fall into the cylinder head when you remove the cover. Once you have removed the cover, stick a piece of cardboard over the cylinder head(s) so nothing drops onto the valve train. Depending on the type of engine, and especially mileage, if you are going to the trouble of removing the valve covers you might also consider replacing the valve stem oil seals which are a common source of internal engine oil leaks (into the engine cylinders). Also, this is a good time to put in a new PCV valve.

Valve cover retaining bolts (or nuts) MUST be installed using ONLY a calibrated torque wrench and tightened to the exact specification set forth in the Factory Service Manual for your car. If these fasteners are overtightened, or undertightened, you will have wasted your time doing the repair because the assembly will leak once put in service. YourMechanic can replace the valve cover gaskets for you as well as examine the rest of the engine to see if you have any additional oil leaks.