Error Codes and Rust on oil cap

[Nate_2018]

For a few months, I've been getting P0404 codes. Replaced the EGR valve and it went away then came back. I couldn't figure it out so I let it sit and see what would happen. Soon after, on startup, it started having issues starting as well as it had trouble going and had a deep rumbling that would soon dissipate as if I was burning off water, come to find out there is rust in the oil cap and around it so something is seriously wrong. Just the other day I got two new codes P0440 and P0441 and I'm thinking it may not be the worst like a head gasket leak. Hoping to get a second opinion and some more info before I tear apart 3/4 of my engine to not find a head gasket leak

 

[SYKRAMMAN]

The rust in, on, or around your oil cap is just condensation from your crankcase, put and oe cap back on and throw the metal cap out and install a oil catch can, that will minimize the condensation and keep crap from going into your intake.