Trouble removing oil drain bolt on 4.2 A6
 

I'm having trouble removing the oil drain plug on my 2008 4.2 A6. It's a 6 allen head bolt and it's rounded which means that no wrench will do the trick. I've used regular allen keys and a hexagon socket addition with no success on either of them. Does anybody have any suggestions? I'm really at a loss. Thanks.

For the 4.2 I believe it a 10mm opening for the allen key, you can also use an 18/19mm socket, so you just make sure your turning it to the left with significant force and you should be able to get it off. You may want to use a breaker bar, in case you don't quite have the leverage.