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?

Images: https://imgur.com/a/uLjfaGx