Crankcase Depression Regulator (CDR)
WARNING: This page does not describe the selected car, but rather 35 other vehicles, including the 1992 Pontiac Trans Sport, 1992 Oldsmobile Silhouette, 1992 Oldsmobile Bravada, 1992 GMC Yukon, and 1992 GMC Vandura Special. However, it is still accessible from the selected car via links, so may be relevant.
To test CDR valve, connect one hose of a water manometer to engine oil dipstick tube. Leave other hose of manometer open to atmosphere. Install air cleaner and run engine. CDR valve specification is one inch of water pressure at idle to 3-4 inches at full load. Add amount of distance water travels down one side of gauge to distance water travels up other side of gauge to obtain reading.