Engine oil emulsified - Mercedes v6 petrol?

Engine oil can become emulsified (milky white color) from a build-up of water in the crankcase. Normally it is condensation resulting from or caused by short trips in cold weather. The engine isn't allowed to reach operating temperature and the moisture is not driven off by the heat. Other causes can be a coolant leak, but antifreeze ususally turns the oil jet black.

If you don't get out on the highway frequently, then make it a point to do so once a week. If it has been too long since you changed the oil then do so. Water and combustion by-products not only weaken the lubricity of the oil and lead to higher engine wear, but water increases the acidity of the oil and eats away at metal surfaces.