Exhaust Emissions System - Crankcase Ventilation: Description
Crankcase Ventilation system consists of a "T" nipple connected to throttle valve housing, a hose from valve cover to "T" nipple, and a second hose from air cleaner to "T" nipple. The "T" nipple contains a restricted orifice to give the crankcase proper vacuum.
When crankcase pressure rises, air flows from valve cover, through nipple to intake manifold. If crankcase pressure is too low, air flows from air cleaner into intake manifold. This action allows any blow-by gases to be drawn into intake manifold and hence be burned by the engine.
NOTE:
Some 1976-77 models will have an "L" nipple on top of Inlet manifold. This system was modified to accept air conditioning by using only one hose from valve cover to Inlet manifold and replacing the "T" nipple.
Models that have been modified in accordance with Saab carburetor icing modification, have the hose from valve cover routed to the air cleaner adapter. In addition, a fast idle valve is installed in the same location that the "T" nipple used to be. These changes will not affect operation of the crankcase ventilation system.
Models that have been modified in accordance with Saab carburetor icing modification, have the hose from valve cover routed to the air cleaner adapter. In addition, a fast idle valve is installed in the same location that the "T" nipple used to be. These changes will not affect operation of the crankcase ventilation system.