Earlier in the year, I checked my car's oil level. It was a hair under full, so I wasn't concerned. Then, for the past week, I've been getting a yellow oil light coming on after the car was shut off, so I finally decided to research it. It means to put oil in because it's getting low. I found that really odd because it didn't eat oil at all in the few months before, so I shrugged it off and went for my quart of oil.
I went downstairs, opened the hood, and checked the oil. Sure enough, it was down to the minimum marker. Shocked, I reached for the oil filler cap, and my jaw dropped as far as it can possibly go.
I saw the mustardy substance all over the underside of my filler cap, and a little bit into the hole. I've attached photos:
I am scared shitless right now. What the heck is going on????? I can't possibly have a bad head gasket!?!?! The car wasn't overheated whatsoever!
Is there any other explanation?