I have a 95 maxima with 140K. I have developed an oil leak. The shop told me it was the valve covers gaskets. They fixed them but that was not the entire problem. Now when I start the car after it has sat overnight it will leak about 25-30 drops and then quit leaking. It looks to be comming from above the oil filter and below the valve covers. I do see a little oil on the rear ehxaust bolts but just a little bit. There is also oil on the main seal that goes around the bottom of the cylinder block. Not sure if that has dripped from above or if that gasket is leaking.

What would make the car leak when it is started cold and then stop leaking?? Thanks