Cooling System Diagram
- Coolant reservoir
- Coolant pump
- Thermostat housing
- Heat exchanger, cabin
- Throttle body
- Oil cooler (aut. only)
- Engine temperature sensor
- Shut-off valve
- Radiator fan
The cooling system is of the pressurized type with cross-flow radiator and expansion tank.
The water pump is on the right-hand side of the engine and driven by the crankshaft pulley via a multigroove belt. The thermostat is placed in a housing on the left-hand side of the engine.
The expansion tank is mounted in the engine bay on the left-hand side. It is connected to the coolant pump and the upper right-hand part of the radiator. The purpose of the latter connection is to vent the cooling system. The fluid in the expansion tank does form part of the circulation fluid.
The car is fitted with an electric radiator fan mounted behind the radiator. The fan has either one or two motors, each with two speeds: low and high. Cars without A/C have one fan motor while cars with A/C have two fan motors.
From the coolant pump - via a passage into the engine block – up through the cylinder head – through the thermostat housing's lower outlet – through the hose to the heat exchanger – through the return hose from the heat exchanger – back to the pump.
With the thermostat normally open (1)
From the coolant pump – via a passage into the engine block - up through the cylinder head – through the thermostat housing's upper outlet (past the thermostat) – through the radiator – back to the pump.
A small quantity of coolant passes through the thermostat's lower outlet to the heat exchanger and back to the coolant pump.
With the thermostat fully open (2)
The thermostat closes the lower passage through the thermostat housing thus forcing the full flow of coolant through the radiator.
Radiator fans download: Radiator fans - Saab 9-5 4-cylinder.pdf