This problem has been around for a while. A brown foam forms around the dipstick and I have been changing the oil every few months to keep things going along. One guess is that there is coolant getting into the oil, but I have also heard that short drives where the engine doesnt get all that warm will also cause the problem. My drive to work is about 5 miles and although the engine comes up to temperature, it can't be getting all that warm in such a short distance. Car currently has over 180k miles on it and nothing major has ever been done to the engine. Any ideas as to what is happening here?
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97 S90 with 178K miles still going strong

Head gaskets can fail in many ways, i've realized, since I've replaced two on B230F engines in recent year. I was loosing coolant in the 765 following an overheat incident (change those heater valves as preventive maintenance, this one failed at 160K). Coolant loss increased until BIG cloud of white smoke or steam billowed from exhaust. Oil also looked like chocolate milk at that point. had head shaved .010, changed head gasket and car's now running fine. Tough engines.

on the 945, i saw evidence of trickle, more like dry mineral deposit, at head gasket joint near No. 1 cylinder, exhaust side. so I spent the weekend doing that head to avoid a bigger problem.

in both cases, the head gasket near the coolant galley of No. 1 had deterioated, allowing coolant to leak into oil galley/combution chamber (765) and on the 945, from the coolant galley out the engine block, exhaust side. It pays to watch for leaks around the head gasket, or coolant loss, to stave off later trouble.
chris in vermont, 244, 945, 765 (sold and still runnin' fine)

Has your coolant level been going down at all?

With hind sight, I realized my car had some of this "foam" on the dip stick and in the flame trap as well. My car was taking about 1pt of coolant every 2 weeks and I could see some coolant on the rear cross support under the back of the engine. I had the system pressure tested at the dealer and they found the external leakage between the head and block on the back passenger side corner. Once I had the head off, from the leakage path, I realized there was probably some coolant leaking into the oil as well. For some reason the gasket just seemed to have deteriated in that corner. The head and block were fine. I had the head pressure tested, valves vacuum checked and a skim cut done to ensure a good surface for the new gasket.

If your coolant level is stable, it is probably just condensation. If you want to ease your mind you could have an oil analysis done. "Google" for Oil Analysis and you should find a couple places to have it done for say $20.00 or less.

Keep us posted.
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'96 965, 16' wheels, rear 18mm bar & Koni + 204HP cams at 122K. Had '85 745 Turbo Diesel for 200K.

I've seen this on my 96 960 with 200K.
I haven't seen it lately though!?
I do have a faint coolant smell on occasin from the heater so I see a bottle of Bars Leaks in my future.
Consider one yourself.

Tom

Not sure what's going on with you, but I can tell you that my V90 does not display similar findings with almost the same driving characteristics. I drive less than 3 miles a day; engine reaches operating temperature, heat kicks in, etc. I suspect from my difference that you have another problem causing this; as you suggest a possible coolant leak
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John Shatzer, '97 V90 @ 105K

Probably condensation on the dipstick. Watch the coolant level carefully for any declines: that will be a clue.

pressure test the cooling system, that will tell you if there is infact any leakage. I've seen a few headgaskets go in these cars.
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cjregensurger@yahoo.com '86, '88 740 GLE; '88, 89 740 Turbo, '88 760 Ti