There is vacuum control on the elbow fitting attaching the 1" or so rubber hose from the top of the oil fume separator on the front driver's side of the block to the intake air tract just before the throttle plate. I assume the fitting/valve opens the vent passage at higher revs (low vacuum)but what are the specs and what controls the vacuum signal? I have oil seepage up in the area of the ps pump and alternator, can't see much. Could be a pressure issue. Hope it is not a thin block or the head gasket. Do the oil separators crack or leak?

I don't have any expensive Volvo books, unfortunately...