volvo coolant issue

Oil In Coolant Issue

After a few weeks of running perfectly (even better than before because it use to hunt at juctions, lights etc, and be very smoky when putting the pedal to the floor) and still runs great apart from the oil is now disappearing from the sump into the coolant expansion bottle. the condition of the oil in the expansion bottle is as new it has not even starting to turn into milkshake.