Car: 2008 Audi S5 4.2L
I found an oil leak at the bottom of my car near the engine/trans, which lead me to believe the rear main seal. However, one mechanic told me it was the timing cover gasket, while another told me it's the valve cover gasket.
I had a look at the engine bay from top and it looks like there is quite a severe leak, however I'm not sure if it's the valve cover gasket, or the seal under the guide frame (part 11, valve cover sits on top of it):
Here's a picture of what I saw (the top gasket is between the valve cover & guide frame, bottom is between guide frame and head). Also note the huge mound of gunk behind the plug:
Here's a picture after I washed it down with degreaser:
Became liquid naturally falls down and back when accelerating, I think it is in fact the valve cover, and not the seal under the guide frame. However, I'm not sure. What are some signs that it is the valve cover gasket or not?