Thanks for the replies guys. Just to clarify, I want to remove the whole s/c tensioner (spring housing plus pulley), not just the pulley. The spring housing is held by a single torx bolt thru the middle of the spring housing, surrounded by that star shape. I'm pretty sure it's a TORX E8, but it seems like it can strip so easily (I tried it with great pressure in both directions with no luck) so I want to make sure I loosen it the correct way.