[cas951]

This is a sign that the car was driven only a short distance. Whenever you start your engine the engine sweats. If normal operating temp is not reached and driven for awhile this is how sludge develop. To prevent this you should never idle for long period or drive short distances. To get rid of this drive it for about 15-20 miles on the freeway. This will evaporate. If you want to see more of it let it idle for 10 minutes or continue to drive shrt distances specially during cold weather.