What do you think would be the cuase of the oil leak above the driver side exhuast manifold?
The most common oil leak on these engines is the valve cover gaskets. The gaskets are a mix of rubber and metal or plastic and the rubber will get hard and will not seal very well when the engine is cool and then seals up as the engine warms. The newer gaskets on the market have better sealing compounds built in the gasket material rubber. Have the valve cover gaskets replaced on both sides.