Tighten The Timing Belt And Check
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2006 Volvo S80, 2005 Volvo S80, 2004 Volvo S80, 2003 Volvo S80, and 2002 Volvo S80. However, it is still accessible from the selected car via links, so may be relevant.
Pull the lock pin out of the tensioner / damping unit.
Install the pulley for the auxiliaries belt.
Install the crankshaft center nut.
Turn the crankshaft two revolutions and check that the markings on the crankshaft and camshaft pulleys align.