97 expedition

i have a 97 expedition just noticed when i went to add some oil there was a little milkey color on the oil cap the engine hasnt overheated temp doesnt get any higher then usaul none on the dipstick just on the oil cap itself any help would be great thanks.is it somthing to worry about or something i need to change thanks ones agian

If there has been a temperature change recently, a little skim is just condensation and is nothing to worry about.