There is a simple check to see if your PCV is really the problem: Replace the oil fill cap with a pressure gauge. If there is positive pressure while the engine is running, the PCV system may be your problem. If negative (i.e. vacuum), then you're probably still OK. Your local garage can check this quickly. For what it's worth, the service manual says to clean at 60k and 100k.

If you have to tackle this (or just decide to anyway), beware it is no small job! To get to the oil separator, the intake manifold has to come off, requiring removal of the fuel rail/injectors and the throttle body. Plus, some of the bolts on the manifold are difficult to get at. It would be a good time for your tune-up, though, because one of the PCV lines runs back to the firewall area, and it's much easier to change with the distributor cap and ignition wires out of the way.
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1998 S70 T5, 5-speed, 140k