What's the problem?
Poor or no maintenance, using the wrong oil grade or frequent short journeys will add to the problems associated with the flawed PCV(Breather system).
The old method of suction to remove oil via the filler neck also prevented particles of sludge from being drained.
The PCV (Breather System) breaks down causing blockages leading to oil starvation, symptoms can include:
Soft/mushy PCV Pipework
Oil leaks
Increased Oil consumption
Blue Smoke
Turbo failure
Whine immediately upon start up (which may dissapear as the engine warms)
Oil Pump failure (resulting in total engine failure)
Models other than the Aero were specified to run on semi synthetic oils, these oils would under some circumstances break down too quickly.
http://www.thesaabsite.com/95/95faqs.htm#10,000_Oil_Service_and_Our_thoughts
For many years oil pickup problems have cause a variety of engine problems on Saabs. Oil pressure issues, Main/Rod bearing issues, Timing chain issues etc..... We are seeing even more problems with the oil pickups getting clogged up on the 93.95 cars now that the oil replacement recommendations have increased. We are seeing more and more issues with the lower ends of the engines beginning to scream or make a high pitches whining noise due to low oil pressure to the upper end of the engine. When the timing chains are being replaced we HIGHLY recommend cleaning or replacing the oil pickup tube as well. We also do NOT recommend changing the oil at intervals that are higher than 5000.00 miles. Not everyone runs synthetic oil all the time and synthetic is not available at every store in the world.
HOW DO I DETERMINE IF MY OIL PICKUP TUBE IS CLOGGED UP?
One of the most common issues with Saab engines is a clogged up oil pickup tube. Paraffin based oils will cause build up on the oil pickup screen causing the engine components that are farthest away from the oil supply to make noise. i.e.....Valve train, lifters etc.... You will likely find that the waxy build up begins to block the screen. This is usually caused by too long of a time between oil changes. The only real fix is to remove the oil pan on the 9000, NG900, 93, 95