I am forgetting how it is on the internal water pump version of the 1.8, but isn't the belt tensioner roller attached with 3 bolts only? Its fairly easy to remove those 3 without doing much more than releasing the belt, no?
The viscous fan roller bearing might also be the cause. With the belt off, check that this one spins freely and doesnt have any play.
The viscous fan roller bearing might also be the cause. With the belt off, check that this one spins freely and doesnt have any play.