There is a large hose from the flame trap that goes to the engine air intake before the fuel injection system. There is also a small hose from the flame trap to a fitting on the intake manifold. If you remove both and alternately cover and blow into these, you will determine if the flame trap and the rest of the crankcase vent system is free or blocked. The parts are inexpensive and a relocation kit makes things easier in the future.

It is true 240 series Volvos don't have PCV valves which are a one way check valve. They have flame traps instead. Both prevent flame from a backfire in the intake from reaching the fumes in the crankcase.

Since you quote your odometer in kilometers, you may have a 2.3 liter engine. Volvo produced 1.7, 1.8, 1.9, 2.1, and 2.3 liter versions depending on what region it was sold. If you give us your complete VIN number, we can look it up.