The positive crankcase ventilation valve, or "PCV" valve on your Saab vents gases from the crankcase to keep excessive pressure from building up inside the engine. This valve also recirculates gases back into the engine for more complete burning. Over time, this valve becomes dirty from normal engine operation and will need to be replaced. The valve on your Saab is made of white plastic and is attached to the side of the engine's crankcase on the bottom of the engine. Fortunately, the PCV valve on your Saab can still be reached from the top of the engine.
Open the hood of your Saab and locate the PCV valve towards the bottom of the engine. The PCV valve location varies slightly depending on the specific Saab you're driving, but all of Saab's PCV valves are white rubber and are stuck into the side of the crankcase on the bottom part of the engine.
Grab the end of the plug with a pair of needle-nosed pliers and twist the PCV valve back and forth while pulling it out of the engine. If it's been on there for a while, it may be very difficult to remove.
Pull the hose off the end of the PCV valve (the side that was not plugged into the engine).
Secure the hose from the old PCV valve to the new PCV valve and plug the PCV valve into the engine's crankcase.
