How do I cure this oil leak?

[Joe H]

I have oil pooling under the plastic cover of my 1999 V70 Petrol, non-turbo.
I assumed I had been careless topping up so cleaned it and it returned. Changed the oil cap gasket and it returned. I have slightly negative crankcase pressure btw.

Finally I covered the area with talc powder (nice smell...) and it seems to be just appearing beside cylinder 5.
In this photo the pool appeared from dry in 5 miles so it is not trivial, but nothing appears when I leave it idling so I can observe it. There is no sign of it tracking from the oil cap area or anywhere else.

So what is going on? I assume it is seeping past one of the 2 arrowed bolts but I am not sure what their purpose is and don't want to be randomly tightening them to find I have made matters worse by disturbing the cam cover seal for example.

[Joe H]

In case it helps anyone else...it seems the leak was from the hex-head bolt on the right.
Still not sure what it's purpose is - anyone know?
Cheers
Joe

[ITSv40]

From your photo it looks like one of the cam cover bolts. It would also explain the oil leak if it was loose.