Hi, and welcome to Brickboard.

You definitely should check your flame trap. The Volvo 240 and later pcv system is different from most, has no pcv valve. Instead it has a flame trap which tends to get clogged up with oil gunk. Your oil in the air filter could be caused by that flame trap being clogged up. I usually see oil at the throttle body and at that end of the air intake hose, but not all the way up front at the filter.

Any time we hear of oil leaks in a 240 we say "check your flame trap" because when clogged it seals the crankcase and oil leaks out wherever it can.

Here's the link to the section in the FAQ.
http://www.brickboard.com/FAQ/700-900/EngineSealsBeltsVent.htm#Crankcase_Ventilation_A_Treatise
The flame trap is under the intake manifold as it describes.
You can get the parts from fcpgroton.com for just a few small dollars.

I like to remove the idle air control and maybe the throttle body to get decent access under there, but that's just my own preference. It's possible to get your hand in to the flame trap without removing other stuff first.

Good luck and let us know how it works out!
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Sven: '89 245 NA, 951 ECU, expanded air dam, forward belly pan reaches oem belly pan, airbox heater upgraded, E-fan, 205/65-15 at 50 psi, IPD sways, no a/c-p/s belt, E-Codes, amber front corner reflectors, aero front face, quad horns, tach, small clock.