Lesson 4/Learning Event 2
FIGURE 64. DRAFT TUBE SYSTEM.
One of the ventilation systems used on automotive engines is shown. Air is drawn into the crankcase through
openings in the valve cover. The air circulates around the crankcase and above the oil in the oil pan. The
blow by gases and the fuel and water vapors are mixed with the air. This mixture is drawn out of the
crankcase through the road draft tube and discharged into the surrounding air as the car travels down the road.