Originally Posted by RamTech
What you see in the inside of your cap isn't always a good indicator of what the inside of the engine looks like.
The oil fill spout is elevated and is plastic. Plastic does not transfer heat.
What you're seeing is oil vapors that rise in that tube, and are exposed to cooler air, causing condensation, hence the tan, gooie, build up you get.
Short trips where the engine doesn't reach full operating temps long enough to dry it out, will make it worse. Not to mention, the PCV valve is there, sucking engine/oil vapor up to that location.
Ford had the same issue on the older small block engines, at the oil fill cap, where the PCV fit into.
It's harmless.....just really annoying to see, and you'll see it more in the winter/coller months then you will in the summer, because of the warmer, summer ambient temps.