Did you have the white smoke before it got cold outside? A gasoline engine produces a great deal of water when it runs. That's why water pours out the tailpipe on some occasions. I had a blown head gasket on a Suburban, it produced CLOUDS of steam even when hot.

What I did when I saw gunk on our 850's dipstick was to warm the car up with a good 30 minute drive. Then I took the dipstick out and cleaned it top to bottom. Then I tied a piece of soft cotton twine around the tip of the dipstick and ran it up along the stick to the handle. I put the stick in and out until I had cleaned all the gunk out of the dipstick tube. I tied a clean piece of twine on and confirmed that the tube was clean.

I then took another 30 minute drive and checked the oil - no more gunk.

I now clean the dipstick from top to botton weekly when I check the oil, this minimizes the gunk that I find on the stick.
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96 855R, 95 855,854, 90 744 Ti - 340,000 Volvo miles put on 7 bricks