When I bought my used truck I noticed oil around the valve cover gaskets. I cleaned the top of the engine and replaced the gaskets. I am slowly starting to see a little oil around the gaskets. What's the deal here?

 

You have a leak?

 

Have you retorqued the bolts? 18 ft/lbs. Did you replace the o-rings that are under the bolt heads, at the same time?

Are the valve covers seated properly? How long since you replaced the gaskets?

 

I did replace the o rings at the same time. I'm pretty sure they are properly seated. I don't have a torque wrench, but I got them good and snug. I might double check that though. Any other thoughts?

 

You really should use a torque wrench, too tight is just as likely to cause leaks as too loose.