I just bought a 2012 XC60 T6 AWD a couple weeks ago that's been whipping my butt. Has 100k on it, got it for $13,000 which seemed like a deal...

Anyways, after much swearing, stress, and a sleepless night, I resealed the vacuum pump, which was the only major malady. I then decided to change the oil so I'd know when exactly it was done. So I went to Volvo and bought the filter kit, air filter, cabin filter, and O'reilley's to get a 12 point 36mm socket for the filter. I get under there, remove the plastic, and find the drain bolt is rounded. I get it off with my rounded bolt remover tool, oil drains out. I jump in the spare car (every time I consider selling one, I'm reminded why I have 2) and go to Autozone and buy a new plug. They sell me a B18-1.5 and tell me it'll work, despite it being a bit shorter than the original. I go home, install the aluminum washer, put the plug in, finish the filter, add the fresh oil, and start it up. After a brief drive, I park it in the driveway because the garage was a huge mess with oil. Go out to move it an hour later and there's, like, a LAKE under my car. Thinking I didn't tighten enough (horrible habit of breaking bolts) I get under there and tighten as hard as I dare. It seemed to slow it down, but I still leave an empty quart container under it to catch the mess. I've only driven it once since and in 4 days, it's only leaked 1/4 of a quart. What do I do? Local shop quoted $1400 for new pan, but never drained oil to inspect.

 

M18-1.50 is the size that is called out.
Since the old bolt was rounded, the pan might have been compromised.
Was it leaking before the oil change?
If not, I would pull the plug, and drain the oil into a clean pan.
I'd purchase a new plug and aluminum washer and install, snug it up but don't over tighten and reinstall the oil your drained back in and check for leaks.
I wouldn't replace the pan unless it was stripped.

 

I couldn't remember if it was B or M. I got fed up with it sitting there in the garage mocking me and took it to a different shop, who on inspection said it was the totally wrong plug for the vehicle. They charged me just under $200 to dispose of my brand new castrol edge, rethread the pan with a bigger plug, and top up with fresh Pennzoil (ew-but it's what they used). Got it back Monday night, hasn't leaked a drop. I am a blithering idiot with no business even attempting to work on this vehicle. Painful and expensive (though not as bad as it could have been) lesson learned, but thanks anyway.