Car: 1997 328i 5-speed, 160k miles I check my oil every week like a good BMW owner. Lately is has been extremely cold here, hitting -15ÃƒÆ’Ã†â€™ÃƒÂ¢Ã¢â€šÂ¬Ã…Â¡ÃƒÆ’Ã¢â‚¬Å¡Ãƒâ€šÃ‚Â°F a couple of days. The underside of my oil cap looks like this: This happened last year about this time, and I thought I had a blown head gasket. The people over at Bimmerforums convinced me it was just moisture in the oil (since the milky yellow stuff wasn't in the oil at all) and sure enough when it got nicer out it went away. It's happening again, and I just want to know if it's going to harm anything. I thought maybe I had a PCV valve going bad but I can't find anything in my Bentley manual or online, so I don't know if my car even has one.