I agree with Pretty White in that it's more "sweat" than a leak. My '99 Sentra SE with 49K miles has the same problem. Just a slight amount seeps out near the end of the cams. I took the car up to the Nissan dealership today and they are replacing it under warrenty with no questions asked. Actually, I was just planning on buying a gasket and putting it on myself but they offered to do it under the 60K mile power train warrenty! Hopefully it won't do it again. BTW- I was running Mobil 1 10W30 Synthetic oil but it started before I switched to synthetic.