Several of our customers with late model GM vehicles notice that between oil changes, the engine oil level is low. Several of these customers even have to add oil between changes because the oil level drops below the "ADD" line on the dipstick. This can be caused by deposits left in the crankcase by the engine oil. We have even found that the PCV passages in the left (driver's side) are restricted or even plugged allowing engine oil to be drawn directly into the intake manifold. GM has released a new valve cover design to combat this problem as well as a pressure regulator baffle to be installed in the oil pan. The pictures show a "Good" and a "Failed" valve cover, as well as the oil pan baffle.