4-cylinder engine

Cooling System Diagram

1. Radiator
2. Coolant reservoir
3. Coolant pump
4. Engine
5. Thermostat housing
6. Heat exchanger, cabin
7. Throttle body
8. Turbocharger
9. Oil cooler (aut. only)
10. Engine temperature sensor
11. Shut-off valve
12. Radiator fan

Brief description

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.

Coolant flow



Thermostat closed

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

V6 engine

Cooling System Diagram

1. Coolant pump
2. Engine
3. Thermostat
4. Radiator
5. Heat exchanger, cabin
6. Expansion tank
7. Electric pump
8. Oil cooler
9. Throttle body
10. Shut-off valve
11. Turbo
12. Radiator fan

Brief description


The cooling system is of the pressurized type with cross-flow radiator and expansion tank.

The coolant pump and thermostat are located on the right-hand side of the engine. The coolant pump is driven by the crankshaft pulley via multigroove belt.

The expansion tank is mounted in the engine bay on the left-hand side. It is connected to the coolant pump, throttle valve and upper left-hand part of the radiator. Its connection to the throttle valve is for preheating while the purpose of the last-mentioned connection is to vent the cooling system. The fluid in the expansion tank does not form part of the circulation of fluid.

The car is fitted with an electric radiator fan mounted behind the radiator. The fan has two motors, each with two speeds: low and high.

Coolant flow



Thermostat closed

From the coolant pump - via a passage into the engine block - up through the cylinder heads - 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.

From the coolant pump - via a passage into the engine block - up through the cylinder heads - via the bypass passage - back to the pump.

Important
Do not mix up the coolant hoses. Connections: A - Expansion tank, B - Cut-off valve, C - Heat exchanger.



With the thermostat normally open

From the coolant pump - via a passage into the engine block - up through the cylinder heads - 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

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 V6.pdf

Thanks for this!


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