I was inspecting my engine (1.6L N15 Pulsar) yesterday and I noticed some moisture on the rocker cover coming from the oil fill cap. I unscrewed it and it looked like it was allowing some fluid out. I'm thinking the cap might need replacing. 

I then had a look inside the oil fill and noticed what I think might be a crack in what I think might be part of the valve assembly? 

My question is whether you guys believe that's a crack, what component has the crack and how I should go about it? 

[![enter image description here][1]][1]

[![enter image description here][2]][2]

[![enter image description here][3]][3]

[![enter image description here][4]][4]

**Edit**
Something I forgot to mention is that the oil on the dipstick did have a few tiny bubbles in it which I haven't noticed before

  [1]: https://i.sstatic.net/3rWCV.jpg
  [2]: https://i.sstatic.net/w7uRM.jpg
  [3]: https://i.sstatic.net/inme8.jpg
  [4]:
https://i.sstatic.net/iX3M8.jpg