My experience is only as far as 90s, but even if, I wish to have today older thermostat constructions which were easier to replace rather than whole body.
In Panda 1.3 I took it apart and I was able to replace just thermostat unit in the plastic body IF anyone would be selling separate part.
Yes I do from time to time short distances, to work and back. I have two cars, 500L and Panda, so mainly Panda is for work and 500L for holidays only, but, having car parked up for several months is not good enough so I use it to get to work from time to time. My idea of catch can came last week when I had some spare time to sort small smell of oil/diesel in the cab while engine was running. I was worried if breather system was clogged but tested system and not found any issue. I found turbo entry pipe a bit wet'ish, so I understood that greasy stuff comes from breather pipe which is connected near there. Thinking about turbo, throttle, inlet I decided to go for catch can. I never had diesel or any car with turbo before. I cleaned air pipe perfectly, fitted catch can, so I'll see if in few months time pipe will be still clean or dirty.
In between I found diesel/oil fumes smell issue: after fitting catch can I went under car to inspect pack side of engine, to look for breather pipe there. I found pipe badly cracked, tiny breather pipe, back of the engine, hardly seen, right above the sump pan. I have sump pan on my list to replace because is wet, but now I'm unsure because above sump pan this breather pipe was in absolutely disgusting and wet state with three holes in it. Replaced pipe and I'll do few thousands miles and I'll have a look how it looks like then. To me it looks like this system with breather separator is emitting loads of fumes.
Exactly as you said, water vapor goes on top (to turbo), while oil is separated and goes (should) back to sump pan. Well, it goes now after fixing pipe.
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