My car now undenyably burns oil. Big plumes of white smoke out the tailpipe. Very classy. And now, thanks to my recent oil change, it burns Mobil 1 Synthetic, rather than the shitty Castrol GTX I was using before. The various great minds of Subaru forum-ness weigh in on the subject here.

My leading theory is "weak turbo seals". The turbo is mainly cooled with engine oil, and it has seals that prevent the lubricating oil from getting into the air ducts. But when the seals degrade, they let oil by and it burns. Over time this degredation worsens, until the turbo no longer is lubricated properly and it siezes. Then you get to buy a new turbo.

My car doesn't currently burn oil all the time, though. It's only the first time you go to full load after the turbo has been cold. Now, the lame thing is that it doesn't matter how warm the engine is, because if you're coasting or idling, then the turbo never spools and your exhaust gas is never that hot, even though the oil and water temps are both up. But the first time you dump a bunch of pressure into the cold turbo, it coughs smoke. After that it stays clear until it cools again. Irritating.