Thermostat Closed
WARNING: This page is about a different car, the 2001 Saab 9-3. However, it is still accessible from the selected car via links, so may be relevant.
With the thermostat closed the coolant passes from the coolant pump-via a passage in the cylinder block-up through the cylinder head-via the throttle body (preheating) to the thermostat housing-through the lower outlet of the thermostat housing-through a hose to the heat exchanger-through the return hose from the heat exchanger-and back to the coolant pump.
All the coolant goes directly to the pump from the heat exchanger.