My 2000 f350 is leaking oil from a bolt on the passengers side valve cover. it is one of the bolts on top of the valve cover. Can I just remove the bolt and put a rubber washer under it or do i need a new valve cover?

 

due to its age I would probably want to reseal the valve cover. I would think there would be a gasket under there.

 

I would suggest trying to tighten it first, but not much. If it's loose, find the torque spec and bring it to that. If it isn't lose, I'd replace the gasket - which will run you a few. Those gaskets, because they have an electrical connector that runs through them, are pretty pricey. When I re-oringed the injectors on my 7.3, I was very careful not to damage them so I could reuse them.