I have a 1997 with a 7.3 diesel 4x4 with the California emissions control. I have a fuel leak and the diesel if pooling in the top valley of the engine. I changed the fuel pump and checked the filter housing o-rings. They seem okay. There is a circular flat black thing under the turbo pedestal and its very wet with diesel. Does anyone know what this is? Does it have diesel that could leak from it. In need of some advice

 

The disk may be loose. Or has started to leak at the seam possibly. When the engine is cold you may be able to get in there and check it.

Here is a pretty good link on the subject.