Mystery Oil Leak(s) | SwedeSpeed

My ’05 S40 2.4i is leaking oil, but could I tell you where from? No, I could not. When I look around I’m finding oil everywhere in the general vicinity of the rear, driver-side area of the engine bay. There’s no stand-out culprit; even when running the engine for about 20min while laying underneath I couldn’t find anything visibly dripping. The oil pools down low, on the splash-guard, but I’m finding signs of it all the way up by the lower exhaust manifold bolts, and on everything in-between – including the very inside of the passenger-side axle (just before it meets the transmission), making me wonder if the oil is falling on it and being thrown around, making it hard to ID the source?

A few things I checked, and think to not be a problem:

• The Oil Cooler
• The Rear Main Seal
• The Oil Pan Seal + Plug

Two things I thought were unusual:

• As mentioned before, there are dark spots around some of the lower exhaust manifold bolts. Is there some chance oil could seep through those? I really wouldn’t think so.
  • I do sometimes (very rarely) get a bit of smoke coming out of the same general area of engine bay after long drives – I assumed it to be oil hitting the exhaust system.
• Right beneath the throttle body / air intake tube, on the driver-side of the top of the engine, it looks like there are a few oil lines that are covered in oil. Does anybody know what those are called / what they do? They’re my most likely suspect at the moment. (Picture below)

Below are a few crappy pictures I took, but of course I had just wiped everything down in the vain hope I’d be able to find the leak in a relatively clean bay.

Motor Oil on the bottom of the transmission:

Oil on the side of the engine, where it meets the transmission. Does not appear to be coming from here, more so just ending up here (not easy to tell in the picture, but the flywheel is completely dry):

Could not for the life of me get a good shot of this, but circled in red is the oil line below the air intake. It looks to have drops of oil hanging off of it, but I couldn’t get it to actually drip when running the engine. Just to the right of that you can kind of see the exhaust manifold bolts, as well. And yes, everything shiny here is shiny with oil – I did wipe off the axle, but beforehand it was coated:

Oil cooler. The lines the go in/out of it did have oil hanging off of them before cleaning, but they are both filled with coolant, so not a source of oil.

Uncleaned splash-guard (and garage floor…), loosely showing the dispersion of oil. The wet side is the rear.

Once upon a time the PCV membrane did go out in the last 5min of a drive home, leading to that horrible whining sound, but I did not drive on it at all afterwards and replaced it immediately. I did notice the loss of oil before this, though, so not particularly worried about that. Also confirmed that all around the PCV housing is dry as of today.

So, any ideas?