Background:
The car is a 2.5T and has approx 155,000 miles on it. We have not serviced the PCV since purchasing 4-1/2 years ago at 72,000. I doubt if it was serviced before that. The oil has about 5500 miles on it, I generally change oil (full syn) at 5000 miles so I'm slightly overdue.

Observed:
Getting some milky build up on the dipstick. Coolant level is remaining constant, so I assume the moisture in the crankcase is due to atmospheric humidity in conjunction with inadequate crankcase ventilation performance. It failed both the oil cap jiggle test and the rubber glove finger erection test, so I plan to delve into servicing the PCV.

Questions:
Is it absolutely necessary to remove the intake manifold, or would removing just the throttle body provide adequate access. (I was able to replace the hose that runs from the top of the breather box up to the top of the engine, a few months back, by only removing the throttle body.)

Is there a good list of parts needed for the 2.5 T or is there a complete kit available somewhere?

Is it possible that there are small vacuum orifices, like on the red block intakes, of which the cleaning of said orifices may be all that's needed to get it sucking again? Or would that just be delaying the inevitable?

The main reason to service the oil separator box is to replace the 2 air lines. The one that goes around the block to the turbo gets brittle and can crack under the soft cover.

In your case, I suspect that the PTC is clogged. That is where the other air line from the oil separator meets the air intake, just before the turbo. A little hard to remove, you need to take off the air intake line and clean out the PTC. Easy to recognize, it has an electrical plug.

Remove the air intake and clean out the PTC nipple. My understanding is that the PTC cannot be bought separately and only as part of a new air intake line, which is of course expensive.

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My name is Klaus and I am a V♂lv♂holic

Thanks, Klaus - good info. I did some reading and I saw it explained that there are actually two sources for vacuum for the PCV system. One source for idle (possibly the intake manifold?), and then the intake tube source for cruising with open throttle. That would explain the reason for the electrial connection on the PTC as you describe. My guess is that the PTC opens when opening the throttle?? I didn't have an assistant to help me check for vacuum with open throttle, however, I know the vacuum test failed at idle, so I'm thinking there is another vacuum source somewhere that is likely clogged. Anyway, I'll check out what you suggested and see how it goes.

Yes, when the turbo is engaged, the intake manifold goes from negative pressure to positive. This explains the need for the PTC.

You also need to check every vacuum line and nipple going into the manifold. Don't forget the vacuum lines for the boost controller. The older engines had a vacuum line going from the cylinder #1 area, this also tended to fall apart and is very hard to find.
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My name is Klaus and I am a V♂lv♂holic

I just went out and took another look at it (like if I just stare at it long enough it's going to somehow fix itself). The vacuum hose comes out of the intake tube just above the turbo as you said, however, it runs around to the front of the engine and that's where the PTC valve is located.

I'm thinking I just need to bite the bullet and pull the intake off so that I can get good access to everything and do a thorough job, not missing any hoses or fittings.

Volvo always has a habit of moving things! I would suspect that with a car that is only 8 years old, the elbows should be alright. There could be a loose vacuum line somewhere. Your use of synthetic should have kept the oil separator clean, it has a tendancy to clog with dino oil and about 150K miles of city driving.
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My name is Klaus and I am a V♂lv♂holic