Okay, I am sorry if this is a total "beginner" question, but I observed something today which puzzled me. I am changing the glowplugs on my 1987 300TD, so I have the intake manifold and crossover pipe removed. I decided to test my repair by starting the engine. I chose to not worry that unfiltered air would be getting into the engine after seeing that intake manifold (yuck!). After a few minutes of operation, wispy smoke started to come out of the intake pipe (at the green o-ring, just downstream of where the recently removed EGR valve attaches). The smoke didn't smell of coolant (still keeping my fingers crossed about my #14 cylinder head). When I revved the engine for a few seconds, the smoke would disappear. But it would re-appear back at idle.

So is this just blowby/crankase ventilation I am observing? Or is this some odd leakage of exhaust from one side of the turbo to the other? Maybe this is indicative of a blockage in the exhaust system?

I have a golf tee in the vacuum line of the ARV, if that is relevant.

My reason for asking is just to find out if this is a symptom of a failing turbo or some other failure. Or maybe this is totally normal, but not often observed as it is usually hidden in the intake manifold. Thanks for your suggestions.

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1968 220D, w115, /8, OM615, Automatic transmission.
My 1987 300TD wagon was sold and my 2003 W210 E320 wagon was totaled (sheds tear).