2003 VDC Outback 3.0L H6. Replaced the Harmonic Balander (Crankshaft Pulley) a few months back. Then earlier this week, after hearing a bit of a squeal from the Idler Pulley and Belt Tensioner, replaced the Drive Belt, Idler Pulley and Belt Tensioner Assembly for the peace of mind (that was recommended by members here after the Harmonic Balancer/Crankshaft Pulley went). Based on what I've read and seen, if these parts haven't been replaced on your Subaru and you've driven over 90K miles, I'd replace them (and you can keep the originals as spares if you like). Ours lasted 113K miles.
I checked out the old pulleys. Whatever grease was originally in the pulleys, it was just dry powder by now.
Our good indie mechanic was able to do it all parts and labor for replacing the Idler Pulley, Tensioner Assembly and Drive Belt for $230. It got rid of background noise and the squeal.
Fast Forward a few days to today...
Barely drove the car (not more than about 25 miles) when the VDC Light lit up on the dashboard (indicating VDC is now off), followed by the Check Engine light minutes later. Luckily the Check Engine Light went on just as I pulled up to my driveway. Immediately cut the engine and smelled a bit of oil burning. Looked under car and noticed leaking oil.
What could have caused this? I'm having the car towed back to the same garage first thing tomorrow (Saturday) morning.